Choose timezone
Your profile timezone:
5th DRD3 week on Solid State Detectors R&D
→
Europe/Bucharest
Institute of Space Science & National Institute of Materials Physics
Institute of Space Science & National Institute of Materials Physics
National Institute of Statistics
Giulio Pellegrini
(Centro Nacional de Microelectrónica (IMB-CNM-CSIC) (ES)),
Gregor Kramberger
(Jozef Stefan Institute (SI)),
Michael Moll
(CERN)
Description
5th DRD3 week on Solid State Detectors R&D
The 5th DRD3 Week will be held in Bucharest, Romania, from 29 June to 3 July 2025.
Location:
The conference venue is in the National Institute of Statistics located in Bucharest downtown. All sessions will take place in plenary form.
Abstracts:
The registration for abstracts is open until 08 June 2026
In the abstract submission form please indicate the WG which suits best your contribution.
Local Organizing Committee
Registration
Registration form
Participants
216
View full list
-
-
Registration National Institute of Statistics
National Institute of Statistics
-
WG3 (WP3): Extreme fluence and radiation damage characterizationConveners: Ioana Pintilie (National Inst. of Materials Physics (RO)), Dr Joern Schwandt (Hamburg University (DE))
-
1
HADES project - HArdness factor and DEfect studies in Silicon
The HADES project (HArdness factor and DEfect studies in Silicon) aims to provide a comprehensive dataset on particle-dependent radiation damage in silicon detectors across a broad range of particles and energies, spanning from the keV to the multi-GeV regime, including neutron, electron, proton, and gamma radiation. By combining results obtained on irradiations performed at multiple facilities, employing silicon diodes of identical design, and applying standardized characterization procedures, the project ensures methodological consistency and enables cross-comparison of results.
A wide range of complementary measurement techniques (including current–voltage (IV), capacitance–voltage (CV), deep-level transient spectroscopy (DLTS), and thermally stimulated current (TSC)) provides access to both macroscopic device properties and microscopic defect characteristics. By correlating defect-level information with detector performance, the project addresses known limitations of the NIEL hypothesis, in particular improving the understanding of the distinct effects of point defects and defect clusters.
Another central objective is the consolidation and extension of hardness factors within the Non-Ionizing Energy Loss (NIEL) scaling framework. Using leakage current as a robust damage indicator, HADES aims to reduce existing uncertainties and improve the reliability of radiation damage predictions relevant for environments such as the LHC.
Overall, HADES seeks to develop an improved modeling approach beyond traditional NIEL scaling by incorporating the nature of radiation-induced defects. In combination with detailed simulations, this approach enhances the predictive power for silicon detector performance in complex radiation environments.Speaker: Marie Christin Muehlnikel (CERN) -
2
Infrared Spectroscopy on silicon samples irradiated with protons and neutrons up to extreme fluences
Study of Si detectors for radiation tolerance at extreme fluences up to 1e18 neq/cm2 has been suffering from numerous challenges. Defects created in the crystal lattice, compensate the doping by trapping the free charge carriers, causing the depletion region to collapse, resisting the utilization of conventional electrical characterization tools. Infrared absorption measurements are still feasible and can provide new insights into defect formation processes. The FTIR studies of Si pieces irradiated to (extreme) neutron and (low) protons fluences at room temperature is presented. The concentration of defects in both cases has been calculated. A FTIR spectrometer has been successfully integrated with a cryostat for low temperature measurements at CERN, the respective initial results for as-grown and extreme neutron fluence samples are presented.
Speaker: Faiza Rizwan (Cern) -
3
Gain-Layer Project - current status of defect characterization after 1 MeV neutron irradiation
The Gain-Layer project started in the framework of the RD50/DRD3 collaborations and is now one of the WP3 projects in DRD3. It aims to conduct a comprehensive research on defect engineered p-type pad diodes that are mimicking the gain layer in LGADs, understand the acceptor removal process in irradiated p-type Silicon and parametrise it for various content of impurities and irradiation fluences, finding in this way proper defect engineering solutions to maximise the radiation hardness of LGADs through defect and material engineering, device engineering and optimization of operational conditions. Thus, 19050 planar n++ − p+ defect engineering Silicon diodes were produced with different content of Boron (2 levels of dopant), Carbon (3 different Carbon implantation doses), Phosphorus (for a partial compensation of Boron doping) and Oxygen, processed on standard and Oxygen-Diffused Float-zone Silicon (FZ and DOFZ) wafers of 2Ωcm and 10Ωcm resistivity p-type substrate resulting in 6 types of flavours for the fabricated Silicon diodes which can be thoroughly investigated from the microscopic point of view over a large fluence range. We will present the status of defect investigations with Deep Level Transient Spectroscopy (DLTS) in these types of diodes after irradiation with 1 MeV neutrons.
Speaker: Ioana Pintilie (National Inst. of Materials Physics (RO)) -
4
Van der Pauw characterisation of acceptor and donor removal in LGAD gain implants
Doping removal is one of the key radiation-damage mechanisms affecting the performance of Low Gain Avalanche Diodes (LGADs). In standard p-type LGADs, the degradation of the gain implant motivated detailed studies of acceptor removal at high initial doping concentrations, of the order of $10^{16}$ $\text{cm}^{-3}$. More recently, the development of new LGAD architectures, such as resistive LGADs, compensated LGADs and NLGADs, has extended this interest to donor removal as well.
A new methodology for the characterisation of radiation-induced doping removal was recently introduced, based on the measurement of sheet resistance variations after irradiation using van der Pauw test structures. This approach was first applied to both acceptor and donor implants with very high peak concentrations, around $10^{19}$ $\text{cm}^{-3}$, located at the Si–SiO$_2$ interface, namely the implants used to form the collection electrodes. The method was validated through a comparison between sheet resistance measurements and TCAD simulations based on SIMS-calibrated doping profiles. That study showed that, for this class of surface implants, donor removal proceeds approximately twice as fast as acceptor removal.
In this contribution, the same methodology is applied to buried acceptor and donor implants with peak concentrations around $10^{16}$ $\text{cm}^{-3}$, representative of the gain implants used in LGAD devices. These measurements will provide new initial-concentration points for the comparison between acceptor and donor removal. In addition, the new FBK NLGAD batch includes n-type gain implants based on both phosphorus and arsenic, allowing the role of different donor species in the removal process to be investigated.
Speaker: Alessandro Fondacci (University of Perugia, INFN Perugia and CERN) -
5
Updates on the PAB activities
Updates on the ongoing activities of the Partial Activation of Boron (PAB) common project will be given. Preliminary results will be shown. The schedule of the PAB batches from CNM and FBK will be discussed.
Speaker: Valentina Sola (Universita e INFN Torino (IT)) -
6
Partial Activation of Boron for Radiation-Hard LGADs: Production and electrical characterization
Low Gain Avalanche Diodes (LGADs) have become the detector technology of choice for precision timing measurements in future high-energy physics experiments, where time resolutions of a few tens of picoseconds are required. However, their performance degrades significantly under irradiation due to acceptor removal in the gain layer, a radiation-induced process that progressively reduces the effective acceptor concentration and suppresses avalanche multiplication. This effect ultimately limits the achievable gain and detector lifetime, posing a major challenge for operation in the harsh radiation environment of the High-Luminosity Large Hadron Collider (HL-LHC). The Partial Activation of Boron (PAB) concept has been proposed as a possible strategy to mitigate this effect by intentionally retaining a controlled fraction of boron in an electrically inactive state, creating a reservoir that could potentially compensate for radiation-induced acceptor loss. The effectiveness of this approach under irradiation remains to be verified through dedicated irradiation studies.
This work presents the electrical characterization of LGAD test structures fabricated at Fondazione Bruno Kessler (FBK) within the LGAD_PAB process split campaign, comprising 18 wafers. Three PAB implementation strategies were investigated: partial activation through furnace annealing, partial activation using Rapid Thermal Annealing (RTA), and the introduction of additional inactive boron following full gain-layer activation. Carbon co-implantation was also explored in selected process splits.
Fabricated 1 × 1 mm² LGAD structures were characterized through current–voltage (IV) measurements and gain measurements performed with a near-infrared (NIR) LED setup operated in steady-state mode. The results show that furnace annealing provides effective control of gain-layer activation, with breakdown voltage exhibiting a clear dependence on annealing conditions. Dose 2 wafers processed at intermediate annealing temperatures (T2–T2.5) displayed stable multiplication behavior, whereas higher-dose splits (Dose 2.4) and RTA-processed wafers exhibited excessive gain and premature breakdown, indicating over-activation. Carbon co-implantation reduced leakage current and modified the effective gain. Overall, the study demonstrates that partial boron activation can be used as an effective gain-engineering tool in LGADs, through different process approaches. The comparison of the various PAB implementations of pre-irradiated samples, provides valuable insight into the role of activation conditions in determining device performance and establishes a foundation for future irradiation studies aimed at assessing the radiation tolerance of the technology.Speaker: Syed Muhammad Abouzar Sarfraz (fondazione bruno kessler FBK) -
11:15
Coffee break
-
7
Systematic Investigation of Acceptor Removal in HPK LGADs with Modified Gain Layers
Low-Gain Avalanche Diodes (LGADs) are fast silicon sensors with internal charge multiplication and are key candidates for precision timing layers in future high-energy hadron colliders. Their operation in harsh radiation environments, however, is limited by acceptor removal in the gain layer, which reduces the active acceptor concentration and degrades the internal electric field required for avalanche multiplication. Improving the radiation tolerance of the gain layer is therefore essential for future 4D tracking applications. In this work, we investigated several LGAD prototypes produced in collaboration with Hamamatsu Photonics K.K. (HPK), featuring modified gain-layer designs, including oxygen-modified, carbon-implanted, and boron--phosphorus compensated structures. The sensors were studied after proton and reactor-neutron irradiation. Radiation tolerance was characterized using the acceptor-removal coefficient extracted from IV measurements and the operation voltage required to recover the timing performance after irradiation. The results show that carbon implantation is the only approach among those studied here that provides a clear improvement in radiation tolerance. In contrast, neither oxygen-related modification, including the Partially Activated Boron (PAB) approach, nor gain-layer compensation alone yields a significant improvement, and the compensated carbon-implanted structure shows no clear advantage over the carbon-only case. In addition, the acceptor-removal coefficient is found to depend on the irradiation particle type and energy.
Speaker: Koji Nakamura (KEK High Energy Accelerator Research Organization (JP)) -
8
Laser trap spectroscopy: Depth profiling of cluster formation inside irradiated PIN diode
In this presentation we report the first results from the feasibility study on the laser defect spectroscopy that has been conduced at the ELI ERIC using fs-laser. We are interested in spatial location of the defects (clusters) and in their type/character. The investigated methodology is based on the Transient Current Technique (TCT) using the unique wavelength-tunable femtosecond laser system available at ELI Beamlines. Irradiated silicon PIN diodes (1e16 neq/cm2) is illuminated with sub-band-gap laser pulses in the 1107–2500 nm range, while maintaining laser powers below the multiphoton absorption threshold (referenced to non-irradiated sensors) to ensure that the measured signals originate exclusively from radiation-induced defect states. Very tightly focused beam (< 3um in xy plane) was moved with micrometer precision across the sensor volume to identify location and density (clusters) of the defects. By recording transient current waveforms as a function of wavelength, the energy levels and signatures of different defect populations will be identified. 2D lateral scans of the signal amplitude, will be recorded at the PIN's different depths in order to investigate the cluster defect formation dependence on the depth of the investigated device
Speakers: Prof. Gordana Lastovicka Medin (Faculty of Natural Sciences and Mathematics, University of Montenegro (ME)), Dr Rogelio Palomo Pinto (Dept. of Electronic, Engineering School of Engineering, University of Sevilla) -
9
Study of ionizing energy losses in silicon and silicon carbide sensors with Timepix3
Our study investigates ionizing energy losses (IEL) in silicon following fast neutron impacts between 200 keV and 15 MeV. Using a silicon Timepix3 detector at the Los Alamos Neutron Science Center (LANSCE), a time-of-flight technique was employed to precisely correlate recorded ionizing events with specific neutron energies. The research addresses the competition between IEL and non-ionizing energy losses (NIEL), which is traditionally described by theoretical partition functions such as those proposed by Lindhard and Akkerman-Barak. High-resolution experimental data reveal that while existing models offer partial agreement, they do not fully capture the observed behavior across all energy ranges. Consequently, we provide refined empirical fits and a new universal function to better describe these energy deposition processes. These results significantly reduce uncertainties for displacement damage modeling in silicon-based sensors operating in harsh radiation environments. Additionally, a comparison with data concerning ionizing energy losses in silicon carbide will also be presented.
Speaker: Dr Radu-Emanuel Mihai (Institute of Experimental and Applied Physics - Czech Technical University in Prague)
-
1
-
Social Events: Lunch
-
WG3 (WP3): Extreme fluence and radiation damage characterizationConveners: Ioana Pintilie (National Inst. of Materials Physics (RO)), Dr Joern Schwandt (Hamburg University (DE))
-
10
Annealing behaviour of bulk radiation damage in CMS HGCAL silicon sensors for fluences from 1e13 to 1.5e16 neq/cm2
To face the higher levels of radiation due to the 10-fold increase in integrated luminosity during the High-Luminosity LHC (HL-LHC) phase with respect to the LHC, the CMS detector will replace the current calorimeter endcaps (CE) with the new High Granularity Calorimeter (HGCAL). It will facilitate the use of particle flow calorimetry with its unprecedented transverse and longitudinal readout and trigger segmentation, with more than 6M readout channels. The electromagnetic section as well as the high-radiation regions of the hadronic section of the HGCAL will be equipped with silicon pad sensors, covering a total area of 620m2.
The silicon sensors are processed on 8-inch p-type wafers with active thicknesses of 300μm, 200μm (both float zone material), and 120μm (epitaxial material) and cut into hexagonal shapes for optimal use of the wafer area and tiling. With each main sensor, several small-sized test structures are hosted on the wafers, used for process quality control and irradiation tests. In order to investigate the radiation-induced bulk damage, the diode test structures of these sensors are irradiated with neutrons at JSI (Jozef Stefan Institute (JSI), Ljubljana). Measurements address leakage current, capacitance and charge collection as a function of the annealing time, from which Hamburg model parameters are extracted.
Previous annealing studies have been performed on silicon diodes from neutron irradiation with fluences from 5e14neq/cm2 to 1.5e16neq/cm2. Annealing temperatures from 5.5°C to 60°C were investigated, allowing temperature scaling of the annealing behaviour. For the thicker and highly irradiated sensors as well as for high annealing times, the depletion voltage often surpassed the reverse bias voltage limit of 900V. In consequence, a limited set of Hamburg model parameters could be extracted.
In this new study, identical silicon diodes were irradiated with neutrons at JSI to lower fluences than before, ranging from 1e13neq/cm2 to 2e14neq/cm2 and subsequently annealed at four different temperatures (20°C, 30oC, 40°C, and 60°C). This allows studying defect evolution in a bias-accessible region (0 - 900 V) as well as direct comparison to the original Hamburg model data set. The study aims to distinguish for the first time the origin of previously observed differences in the Hamburg model parameters, which could be related to differences in bulk material, active thickness and the covered fluence ranges.
Speaker: Ioanna Kalfa (CERN) -
11
Radiation hardness of proton-irradiated LGADs for the ATLAS High Granularity Timing Detector
Low-Gain Avalanche Detectors (LGADs) will be employed in the ATLAS High Granularity Timing Detector (HGTD), which will provide precision timing information during the High-Luminosity LHC era. The sensors will operate in a harsh radiation environment where, in addition to neutrons, a significant fraction of the non-ionizing energy loss (NIEL) originates from charged hadrons. Understanding the impact of proton irradiation on LGAD performance is therefore essential for reliable detector operation throughout the lifetime of the experiment.
To study charged-hadron-induced damage, production HGTD LGAD sensors were irradiated with 24 MeV and 60 MeV protons and subsequently characterised using capacitance-voltage (C–V) and β-source timing measurements.
The results show a clear reduction of the gain-layer depletion voltage with increasing proton fluence, indicating significant acceptor removal and a corresponding loss of internal gain. Acceptor-removal constants were extracted for both proton energies and compared with neutron reference data. The measurements indicate stronger gain-layer degradation under proton irradiation at equivalent NIEL fluences. This behaviour is reflected in reduced collected charge and an increased operating voltage required to maintain comparable timing performance.
These measurements provide important benchmarks for charged-hadron radiation damage in LGADs and contribute to a more realistic assessment of HGTD performance in the mixed radiation environment expected at the High-Luminosity LHC.
Speaker: Iskra Velkovska (Jozef Stefan Institute (SI)) -
12
The Long-term Electrical Characterisation of Irradiated HGCAL Silicon Sensors with Dedicated Annealing Steps
The High-Luminosity LHC (HL-LHC) era will expose silicon detector systems to extreme radiation levels over many years of operation, making a thorough understanding of their long-term electrical behaviour essential. As part of the CMS detector upgrades, the endcap calorimeters will be replaced by the High Granularity Calorimeter (HGCAL), which relies on silicon pad sensors from 8-inch p-type wafers covering approximately 620 m² and is designed to withstand particle fluences up to 1.5×10¹⁶ n_eq/cm² and doses reaching 1.5 MGy. To probe radiation-induced bulk damage for wafer-scale sensors, a set of full and partial production-phase sensors spanning different geometries and thicknesses — including low-density (LD, 1cm2 main pad size) and high-density (HD, 0.5cm2 main pad size) variants — was irradiated with neutrons at the Rhode Island Nuclear Science Center (RINSC), reaching fluences up to 1.4×10¹⁶ n_eq/cm². Per-cell leakage current-voltage (IV) and capacitance-voltage (CV) measurements were collected across isothermal annealing steps at 60°C, spanning durations from 10 to 5000 minutes. The study gives insight into the long-term evolution of the sensors' electrical properties under highly radioactive conditions and into how these devices will behave over the full HL-LHC lifetime. Using this dataset, we test the validity of the Hamburg model on our production sensors, extracting the alpha damage constant and the effective doping concentration as a function of annealing time. We discuss the model's applicability to HGCAL wafer-scale sensors and compare the findings to results obtained with single diodes from the same wafer irradiated with neutrons at JSI, Ljubljana.
Speaker: Ufuk Guney Tok (Cukurova University (TR)) -
13
Degradation of polysilicon bias resistors and loss of strip isolation at fluences beyond HL-LHC
The innermost detector layers at the hadron-hadron Future Circular Collider (FCC-hh) are expected to experience extreme fluences up to 10$^{18}$ n$_{eq}$/cm$^2$, requiring a comprehensive study of radiation damage effects on silicon sensor technology beyond the High-Luminosity Large Hadron Collider (HL-LHC) regime. This work investigates the evolution of the polysilicon bias resistance and inter-strip resistance in test structures and miniature sensors exposed to fluences ranging from the HL-LHC target (1.6$\times$10$^{15}$ n$_{eq}$/cm$^2$) to the FCC-hh target (10$^{18}$ n$_{eq}$/cm$^2$).
Preliminary results reveal a clear deterioration of both parameters with increasing fluence: a decrease of approximately 4 orders of magnitude in the inter-strip resistance, reaching values down to 75 M$\Omega$$\cdot$cm, and an increase of approximately 6 orders of magnitude in the polysilicon bias resistance, becoming non-functional at these extreme fluences. These findings underscore that conventional extrapolation methods fail at extreme fluences and that dedicated studies are needed to improve the radiation hardness of the next generation of silicon strip detectors beyond the HL-LHC era.
Speaker: Javier Fernandez-Tejero (Institut de Microelectrònica de Barcelona (IMB-CNM, CSIC) (ES)) -
14
Effects of Microwave Annealing on Surface and Bulk Defects in Silicon Devices
Bulk and surface defects in semiconductor devices are known to cause negative effects, including increased leakage current and increased charge trapping. Radiation from both high energy photons and particles (typically neutrons or protons) increases these negative effects, and will eventually render the device unusable. Previous studies have been performed demonstrating microwave annealing as an effective technique for low-temperature activation of dopants and reduction of interface defects in some limited applications, but have not considered using microwave annealing in silicon radiation sensors, for mitigating fabrication process or radiation induced defects.
In this study, we investigate the impact of microwave annealing on defects in devices fabricated with sensor-grade float-zone silicon, evaluating their behavior both before and after irradiation. A set of MOS capacitors, gate-controlled diodes, and PIN diodes were irradiated at the Gamma Irradiation Facility (GIF) and PIN diodes were irradiated at the McClellan Nuclear Research Center. Several parameters pertaining to surface and bulk defects are measured for these devices, such as the surface and bulk current density, and interface trap density. Following microwave annealing, improvement in some of these parameters are observed both for unirradiated and irradiated devices. Silicon Photomultipliers were also characterized, with some improvement in the dark current observed.Speaker: Andrew Donald Gentry (University of New Mexico (US)) -
15:40
Coffee break
-
10
-
WG4: SimulationsConveners: Håkan Wennlöf (Nikhef National institute for subatomic physics (NL)), Marco Mandurrino (INFN)
-
15
RASER Simulation of 4D Tracking Solutions
Next-generation particle-physics experiments require detectors capable of simultaneously measuring the hit time and position of incident ionizing particles with high precision, enabling four-dimensional tracking. Conventional LGADs are limited in pixel miniaturization, which motivates the development of alternative architectures such as AC-LGADs, 3D-LGADs, and deep-junction LGADs. RASER, a Python-based simulation framework for solid-state particle detectors, is designed to support the simulation and study of detector concepts for 4D tracking.
Speaker: Chenxi Fu (Chinese Academy of Sciences (CN)) -
16
A surface simulator for resistive silicon detectors
This contribution presents a ROOT-based simulator forsignal sharing in Resistive Silicon Detectors (RSD). The program, controlled by a GUI, simulates signal sharing in a 4 ×4 pixel layout. The program allows to control several parameters such as the pixel size, the surface resistivity, the sensors thickness, the electrode shape, and the presence of trenches or resistors between electrode pairs. The program, via the generation of random signals, predicts the position resolution of a chosen geometries, allowing the identification of the most promising solutions. The program predictions have been compared to test beam results for trench-isolated DCRSD with 3 pixel seizes, 300, 500 and 1000 um, finding very good agreements.
Speaker: Nicolo Cartiglia (INFN Torino (IT)) -
17
A TCAD Simulation Framework for DLTS-based Defect Characterisation in Solid-State Particle Detectors
Defect spectroscopy techniques such as Deep-level Transient Spectroscopy (DLTS) are essential for characterising electrically active defects that affect the performance of semiconductor materials and sensors, particularly in harsh radiation environments. This work presents an update on a TCAD simulation framework developed to reproduce DLTS spectra.
The framework has been applied to several well-known radiation-induced defects in silicon, namely CiOi (carbon-interstitial-oxygen-interstitial), BiOi (boron-interstitial-oxygen-interstitial), V2(+/0) (single-positive donor charge state of the di-vacancy), and I2O (di-self-interstitial-oxygen-interstitial), using defect parameters (concentration, activation energy, and electron/hole capture cross-sections) extracted from current (I-DLTS) and capacitance (C-DLTS) transient measurements performed on p-type silicon p-i-n diodes with a bulk resistivity of 250 Ωcm, irradiated to 0.1, 1, and 2 MGy with a 60Co y-source.
TCAD simulations were carried out by modelling each defect individually in its characteristic temperature range, as well as all four defects simultaneously across the full temperature range. Different trap-filling mechanisms were implemented through laser-induced charge-carrier generation, enabling both majority- and minority-carrier injection depending on wavelength and illumination direction (top or bottom), thus allowing the filling of majority-carrier traps (CiOi, V2(+/0), and I2O) and the minority-carrier trap BiOi.
To assess the reliability of the framework, the resulting simulated spectra were validated against measurements. A systematic shift of the simulated peak positions toward lower temperatures is observed. The origin of this shift, as well as the interplay between combined simulated defects, is currently under investigation. Once this shift is accounted for, the simulated spectra show good agreement with the measured ones in terms of shape, demonstrating the robustness and physical consistency of the simulation framework.
In the long term, this framework is intended to support the validation of defect parameters used in numerical radiation damage models and to enable systematic studies on the impact of individual and combined defects on key device-level observables such as leakage current, depletion voltage, and charge collection efficiency.
Speaker: Tommaso Croci (INFN, Perugia Unit) -
18
TCAD simulations of AC-LGAD sensors: Impact ionization models and influence of temperature
Low Gain Avalanche Diodes (LGAD) are silicon sensors capable of achieving excellent timing resolution due to their characteristic internal avalanche mechanism for signal amplification. Capacitively-coupled LGAD sensor (AC-LGAD or Resistive AC-coupled Silicon Detector (RSD)) improves the granularity of the electrodes, and thus the spatial resolution, without decreasing the active area fraction. This is realized by a gain layer which is implanted over the entire sensor area, while the signal is read out via segmented pads or strips, AC-coupled to silicon with an insulating oxide layer. However, the performance of LGAD is strongly affected by environmental factors such as temperature and humidity. Understanding the evolution of the response of LGAD sensors as a function of these environmental parameters is therefore essential for any application. TCAD simulations have an essential role in the R&D of the AC-LGAD sensors, as they are applied to optimize the design parameters, confirm the experimental results and predict the expected performance. We will present a TCAD simulation study of the temperature effects on the avalanche onset in AC-LGADs with varied epitaxial layer thicknesses. Since an accurate impact ionization model is critical for the LGAD-simulations, a validation investigation between six models (van Overstraeten-de Man, Okuto-Crowell, Lackner, University of Bologna 1&2 and Massey) will be shown. This is realized in terms of breakdown voltages ($V_\textrm{bd}$), charge collection and distributions of impact ionization and electric fields at the gain- and epi-layers. The simulated temperature dependence of $V_\textrm{bd}$ ($V_\textrm{bd}$($T$)) is then compared to the measured results of BNL-fabricated AC-LGADs with varied epi-layer thicknesses. The linear slopes of $V_\textrm{bd}$($T$) are shown to contain information of the epi-layer thickness, with Massey model in close agreement with the experimental results.
Speaker: Dr Timo Hannu Tapani Peltola (Texas Tech University (US)) -
19
WG4 - Updates and DiscussionSpeakers: Håkan Wennlöf (Nikhef National institute for subatomic physics (NL)), Marco Mandurrino (INFN)
-
15
-
Social Events: Reception
-
-
-
WG2 (WP2): Hybrid silicon technologies
-
20
Introduction, news and plansSpeakers: Alessandro Tricoli (Brookhaven National Laboratory (US)), Anna Macchiolo (University of Zurich (CH)), Martin Van Beuzekom (Nikhef National institute for subatomic physics (NL))
-
21
Development of Centimeter-Scale AC-LGAD Sensors for Future Collider Timing Trackers
AC-coupled Low-Gain Avalanche Diode (AC-LGAD) detectors have emerged as promising candidates for next-generation particle tracking systems owing to their excellent timing resolution of approximately 50 ps and spatial resolution of about 10 μm. For large-scale tracking detectors at future collider experiments, centimeter-scale strip AC-LGAD sensors are particularly important for reducing the number of readout channels and simplifying system integration. In this work, we present the simulation, design, and tape-out status of a series of AC-LGAD sensors developed at the Institute of High Energy Physics (IHEP), featuring strip lengths ranging from 1 cm to 4 cm. The effects of n+ layer doping concentration on the electrical performance of the sensors are investigated through detailed I-V and C-V simulations. The impact of isolation structures is also studied by comparing device designs with and without isolation implementations. The electrical properties of AC-LGAD sensors with different process parameters and strip geometries are analyzed and discussed. These studies provide guidance for the optimization of large-area AC-LGAD detectors for future high-energy physics experiments.
Speaker: Mei Zhao (Chinese Academy of Sciences (CN)) -
22
Summary of DC-RSD test beam campaigns
In this contribution, we report the results obtained by combining data from three test beams performed at DESY. DC-RSD matrices with three different pixel sizes (300, 500, and 1000 $\mu$m) were tested on the 5 GeV/c beam line. The spatial resolution shows a linear dependence on the pixel size, remaining consistently better than 5% of the pixel pitch, whereas the temporal resolution exhibits no dependence on the pixel dimensions. Furthermore, this contribution presents a study of events where two pixels were hit simultaneously, demonstrating that even in the case of concurrent events, both spatial and temporal resolutions are only marginally degraded.
Speaker: Roberta Arcidiacono (Universita e INFN Torino (IT)) -
23
TCT measurement campaign of AIDAinnova TI-LGADs production
Trench-Isolated Low-Gain Avalanche Detectors (TI-LGADs) are a promising technology for future silicon timing detectors, combining excellent time resolution with fine segmentation and reduced inactive regions between pads. Within the AIDAinnova framework, a dedicated TI-LGAD production was carried out at FBK to investigate different wafer and design parameters aimed at optimizing the detector performance.
A detailed characterization campaign of these devices has been performed using the Transient Current Technique (TCT). Position-resolved measurements were used to study the charge collection and timing properties across the sensor surface, with particular focus on the inter-pad region. From the collected waveforms, the effective inter-pad distance without gain, the collected charge, and the jitter performance were extracted for sensors featuring different wafer configurations and design parameters. The characterized devices represent unique combinations of structural parameters such as trench width and trench depth, as well as substrate properties like carbon enrichment and gain doping. By evaluating each specific configuration across a broad range of bias voltages, the analysis highlights the physical trade-offs involved and identifies the optimal parameter combinations that balance a minimal inactive inter-pad gap with excellent timing precision.
The measurements provide a comparative overview of the impact of the various process options on the detector performance and give important indications on the choice of the parameters for the upcoming DRD3 TI-LGAD production.
Speaker: Yevhenii Padniuk (University of Zurich (CH)) -
24
Defining the Optical Operating Range of LGAD Technologies
Low Gain Avalanche Detectors (LGADs) are silicon sensors fabricated with a tailored, enhanced electric field layer, which provides internal charge multiplication (gain) that amplifies the output signal and enables an excellent signal-to-noise ratio. Their stable and controlled moderate gain (up to 50), together with an exceptional timing resolution on the order of a few tens of picoseconds, justifies their role as a baseline technology for many HEP experiments, including particle tracking in leading collider experiments (such as those at CERN’s HL-LHC). Originally developed at IMB-CNM [1], this technology has since diversified, with various “flavours” emerging, each intended for different detection applications.
One such “flavour” of LGAD, based on n-type substrates (nLGAD technology), was devised to enhance the detection of low-penetrating radiation (penetration depth ≲ 1 μm), addressing the poor performance shown by standard LGADs fabricated on p-type substrates for this specific application. The viability of nLGAD technology has been confirmed through characterization using 369 nm (UV), 404 nm (blue), 1064 nm (infrared) light, and 600 keV protons [2].
In this study, we carried out a thorough characterization of both standard p-type LGAD and nLGAD sensors under near-IR, visible, and UV illumination (from 250 to 800 nm) at the Extreme Light Infrastructure (ELI ERIC) laser facility (Prague, Czech Republic). For each of the studied wavelengths, we present the experimental responsivity, external and internal quantum efficiency, and the gain for the different samples under test. In addition, we determined, through ellipsometry measurements, the thickness and reflectance of the passivation layers present in each sample, as previous studies on nLGAD sensors [3] emphasized the crucial impact of these intermediate layers, particularly for UV measurements.
Our results confirm that nLGAD devices perform significantly better in the UV range (≲ 400 nm) than standard LGADs, whereas for visible and IR light, standard LGADs are preferable. For photon detection applications, this study defines a clear wavelength range of use for both n-type and p-type LGAD technologies.[1] Pellegrini, G., et al., NIMA 765 (2014), 12-16
[2] Villegas, J.,et al., NIMA 1072 (2025), 170208
[3] Manjolovic, M., et al., Oral Presentation, iWorRID 2025Speaker: Neil Moffat (Consejo Superior de Investigaciones Cientificas (CSIC) (ES)) -
25
Impact of Low-Energy Carbon Ion Irradiation on the Performance of nLGADs
Low Gain Avalanche Detectors (LGADs) are silicon sensors that combine moderate internal charge multiplication with excellent timing performance, reaching resolutions of a few tens of picoseconds. While conventional LGADs are typically based on p-type substrates and optimized for high-energy particle detection, n-type LGADs (nLGADs) have recently emerged as promising candidates for low-energy ion detection, with potential applications in medical imaging and radiation therapy monitoring. However, the impact of low-energy ion irradiation on the performance of nLGADs remains underexplored.
In this work, nLGADs fabricated at IMB-CNM were investigated together with reference PIN diodes lacking a gain layer. The devices were characterized before and after irradiation with 1.0 MeV and 3.1 MeV carbon ions at fluences ranging from 1E10 to 1E11 cm-2. Current-voltage (I-V) and capacitance-voltage (C-V) measurements were performed to evaluate leakage current and effective doping profiles, respectively. Detector gain and timing performance were assessed using the Transient Current Technique (TCT) equipped with a variable-wavelength femtosecond laser system and an optical delay line. The variations in gain and temporal resolution with irradiation regimes, excitation wavelength, and operating temperature were studied. The results showed a degradation of gain and timing performance with increasing irradiation fluence. The gain decreased by approximately a factor of two, while the temporal resolution deteriorated by a similar factor at the highest irradiation fluences. Both parameters also showed a dependence on the laser excitation wavelength, reflecting the influence of the carrier generation depth on the charge collection and multiplication processes.Speaker: Tomas Ceponis (Vilnius University) -
10:25
Coffee Break
-
26
AC-LGAD Timing Tracker Development for Future Colliders
AC-coupled Low-Gain Avalanche Detectors (AC-LGADs) are a promising 4D silicon detector technology for future high-energy physics collider experiments such as CEPC and FCC, offering excellent timing and spatial resolution. This contribution presents recent progress from our team in AC-LGAD sensor R&D, dedicated readout ASIC development (LATRIC), and the establishment of a comprehensive detector testing infrastructure.
For strip-type AC-LGAD sensors, the design targets a timing resolution of ~40 ps and a spatial resolution of about 10 μm. A systematic study of key device structural parameters has been performed to evaluate their impact on timing performance and position resolution, providing essential input for device optimization and design.
To satisfy the stringent readout requirements of AC-LGAD detectors, a dedicated low-power ASIC, LATRIC, has been developed. The single-channel prototype LATRIC0 has completed functional validation, demonstrating key building blocks including front-end amplification, clock distribution, configuration logic, and data readout. In addition, the 8-channel version LATRIC1 has been fabricated and is evaluated. Joint tests of strip AC-LGAD sensors with LATRIC demonstrate the design of sensor–ASIC system and its combined performance.
A dedicated characterization infrastructure has been established, including a laser TCT scanning system and a ⁹⁰Sr β-source test setup, with beam test preparations in progress.
These developments provide a solid basis for the realization of large-area, high-precision 4D silicon tracking systems for future collider experiments.Speaker: JIA JIAN TEOH (中国科学院高能物理研究所(IHEP)) -
27
Exploring the Potential of Low Gain Avalanche Detectors for Low-Energy Ion Spectrometry
Low Gain Avalanche Detectors (LGADs) have emerged as key sensors for High Energy Physics and related applications due to their excellent time resolution and enhanced signal-to-noise ratio. However, their use in low-energy ion spectrometry has generally been limited by gain suppression effects, arising from the high ionization densities produced by such ions within the multiplication layer, which leads to a reduction of the gain and a non-linear detector response with ion energy.
In this work, we investigate an alternative detection configuration aimed at mitigating this effect by shifting the region of highest ionization density away from the gain layer. Alpha spectrometry measurements in the energy range 3-9 MeV were performed by irradiating the detector from both the frontside (multiplication layer side) and the backside of the devices.
The results show that backside irradiation leads to a higher and more uniform gain and a linear relationship between generated charge and alpha particle energy. In addition, the achieved energy resolution is comparable to that of standard PiN detectors. These findings demonstrate the potential of LGADs for low-energy ion spectrometry, particularly in applications where low deposited energy makes enhanced signal-to-noise ratio a critical advantage.
Speaker: Jairo Antonio Villegas Dominguez (Universidad de Sevilla (US) - Centro Nacional de Aceleradores) -
28
DRD3 Project Proposal: AC-DC- Resistive Silicon Detector
Over the last decade, Low-Gain Avalanche Diode sensors (LGADs) and Resistive Silicon Detectors (RSDs) have significantly advanced silicon detector capabilities. LGAD sensors provide much improved time resolution thanks to the fast and large signals with optimised signal-to-noise ratio, achieving resolutions of 30 ps or lower with 50 um-thick sensors. The addition of a resistive readout to LGADs, as in RSD sensors, enables precise concurrent measurement of the particle position, with spatial resolutions below 5% of the sensor pitch. These capabilities make RSDs a very promising candidate for silicon-based 4D tracking detectors of the future High Energy Physics experiments.
The proposed common DRD3 project aims to simulate, fabricate and characterise a new type of sensor based on the RSD technology. Its innovation lies in combining AC- and DC-couplings between the metal electrodes and the resistive layer: large AC-coupled electrodes, read out by fast electronics, provide the time resolution, while smaller DC-coupled pads handle the spatial reconstruction. By assigning timing and position to dedicated readout paths, we seek to improve the current RSD performance while lowering the overall power budget.
This contribution reports on initial 2D proof-of-concept simulations and discusses the proposed sensor structures, which range from pixel-like geometries to larger strip-based designs. A preliminary production strategy and cost estimation are also outlined. The goal of this presentation is to foster feedback within the DRD3 community, along with collecting expressions of interest from institutes willing to participate in the project.
Speaker: Luca Menzio (CERN) -
29
Results from nLGAD sensors fabricated by FBK
The results from an innovative batch of Low-Gain Avalanche Diodes (LGADs) produced by the Fondazione Bruno Kessler (FBK, Italy) will be presented.
The sensors are p-in-n LGADs, where the high-concentration implant that generates charge-carrier multiplication is provided by an n-type dopant (nLGAD). The nLGADs are produced on thin epitaxial n-type substrates, with an active thickness of 55 $\mu$m. Fourteen wafers are produced with different implant diffusions and depths, using Boron on the $p^{++}$ contact and two different dopants, namely Phosphorus and Arsenic, for the $n^+$ implant.
Results from electrical characterisation and signal analysis using TCT, a beta source, and a test beam will be presented, including a discussion on the performance evolution after irradiation up to 1$\cdot$10$^{15}$ n$_{eq}$/cm$^2$.
Speaker: Valentina Sola (Universita e INFN Torino (IT)) -
30
LGAD development at SINTEF
Low Gain Avalanche Diodes (LGADs) have evolved into a key technology in high-energy physics and several other fields. SINTEF initiated its LGAD development with a focus on devices tailored for the detection of shallowly interacting, low energy radiation such as soft X-rays and low-energy electrons. In this context, the internal gain is used to enhance small signals that would otherwise be masked by noise.
Building on this foundation, SINTEF is now expanding the LGAD development activities towards high-energy physics and particle tracking applications. This presentation will discuss ongoing development paths for both p-type and n-type LGADs.
In addition, near-term plans for realizing thin (~50 µm) inverse LGADs (iLGADs) with 100% fill factor will be presented. Combined with fast ASICs, these devices are expected to enable simultaneous per-plane measurements of position and time with high spatial and temporal resolution, targeting precision 4D-tracking in future detector systems.
Speaker: Marius Mæhlum Halvorsen (SINTEF) -
31
Development and Characterization of Si3D Pixel Sensors: Results from the Latest FBK Production Run
This contribution presents the results of the recently completed Si3D production run at FBK, developed in collaboration with INFN Cagliari and University of Trento. The production was mainly aimed at improving the timing performance and radiation hardness of next-generation 3D silicon pixel detectors.
The sensors were designed with pixel pitches of 45 μm and 55 μm, including both single-electrode (1E) and double-electrode (2E) configurations to study the impact of different layouts on detector performance.
This talk will give an overview of the main process splits explored during the fabrication campaign and will present the electrical characterization results obtained on the most relevant test structures and sensors. In particular, IV and CV measurements will be discussed together with preliminary efficiency studies based on TCT measurements.Speaker: Maurizio Boscardin (Fondazione Bruno Kessler (IT))
-
20
-
Social Events: Lunch
-
WG2 (WP2): Hybrid silicon technologies
-
32
Position dependents timing performance investigation on 3D sensors
In this work, we investigate the timing performance and uniformity of double-sided p-type 3D silicon sensors produced by the Centro Nacional de Microelectrónica (CNM) on high-resistivity Czochralski silicon substrates. The studied devices consist of 5 × 5 pixel matrices with hexagonal and square electrode geometries and inter-electrode spacings of 30 μm and 50 μm.
The sensors were first characterized using Technology Computer-Aided Design (TCAD) simulations to study the electric field and weighting field distributions. To investigate the transient signal response, a custom transimpedance preamplifier was developed and combined with a commercial RF amplifier to achieve a high overall voltage gain.
For timing studies relevant to particle physics applications, measurements with a ⁹⁰Sr source were performed to extract the most probable value (MPV) of the collected charge corresponding to minimum ionizing particles (MIPs). Subsequently, a 1064 nm infrared laser with a focused spot size of 2 × 2 μm² was employed to investigate the spatial uniformity of the detector response. The laser intensity was calibrated to reproduce the charge deposited by a MIP, enabling a direct comparison between laser-based measurements and particle-induced signals.Speaker: chuan liao (The High Energy Accelerator Research Organization) -
33
Research development on novel thin 3D sensors based on 8-inch CMOS technology
3D sensors have demonstrated outstanding performance, including radiation resistance, fast response, detection efficiency, power consumption, etc., especially after high radiation fluences. This is mainly due to the shorter drift distance of carriers. These characteristics make them the most attractive sensor technology for charged particle detection and trajectory reconstruction in high-energy physics (HEP). Additionally, its applications have also been explored in astronomy, microdosimetry, and medical imaging. This work introduces a new type of 3D sensor designed and manufactured at the 8-inch CMOS process line of the Institute of Microelectronics, Chinese Academy of Sciences. Its feature is that a trench cathode surrounds the central cylindrical column anode. This new device achieves an ultra-narrow etching width of 0.5 micrometers and an extremely high aspect ratio (>70). Subsequently, the first batch 3D sensors were tested by different institutes, including basic electrical tests, TCT tests, and radiation source tests, etc. The performance parameters tested include dark current, capacitance, collected charge, rise time, time resolution, and gain, etc. The results show that this type of device has a lower dark current and capacitance, time resolution of tens of picoseconds to hundreds of picoseconds, and an internal gain lower than 10.
Speakers: Manwen Liu (Chinese Academy of Sciences (CN)), Gregor Kramberger (Jozef Stefan Institute (SI)) -
34
Characterization studies of a 3D Column-Trench silicon sensor
A novel 3D silicon sensor produced by IMECAS, combining ultra-thin etched columns and trenches, is presented and studied for its timing performance. Several test structures with different electrode widths and pixel pitches were characterized through electrical measurements, laser, and SPS testbeam data.
The devices were first tested using IV and CV measurements. Their timing performance was then studied using a 940 nm picosecond SPA laser. Bias scans show gain in all tested structures, while the uniformity of the gain was investigated across the pixel area and for different laser intensities. An estimation of the time resolution as a function of the bias voltage will also be presented by tuning the laser power to correspond to MIP-like energy deposition.
Testbeam measurements were performed using the Timepix4 telescope, providing a track pointing resolution of approximately 2.3 μm at the DUT position and a reference time resolution of about 15 ps. Signals from the 3D sensor were amplified using CERN's OPTIMA 16-channel amplification board and digitized with SAMPIC. By associating reconstructed tracks with the recorded waveforms, a position-resolved study of the timing behavior of the 3D test structures becomes possible. Preliminary results for intrapixel timing studies based on the available testbeam data will be discussed.
Speaker: Evridki Chatzianagnostou (Nikhef National institute for subatomic physics (NL)) -
35
Deep-Profile Gain, Gain Self-Stabilization and Timing Characterization of Non-irradiated and Irradiated 3D IME-CAS devices fabricated in 8-Inch CMOS Technology
This contribution presents the results of a comprehensive and extensive experimental campaign conducted at the ELI-ERIC facility, focusing on the performance of irradiated and non-irradiated 3D silicon detectors. The investigated sensors include 3D Trench (35 x 35 x 30 um3) and 3D cylindrical single- and multi-pixel devices with column diameters of 10 and 20 um. These advanced structures were fabricated using 8-inch CMOS technology at the Institute of Microelectronics of the Chinese Academy of Sciences (IME-CAS).
A detailed, depth-dependent analysis was performed to evaluate the sensors' internal gain and timing parameters, specifically focusing on Time of Arrival (ToA) and rise time. The experimental results demonstrate remarkable device stability, even when operated at bias voltages very close to breakdown (60 V). This behavior indicates a self-suppression mechanism of the impact ionization gain at the tip of the n+ column, which effectively enables the self-stabilization of the device under high-field conditions. Furthermore, the systematic mapping of 2D charge collection as a function of bias voltage and radiation fluence in the 3D cylindrical devices provides critical baseline data. These insights will be utilized in future work to model and simulate impact ionization phenomena at extreme radiation fluences.
Speaker: Prof. Gordana Lastovicka-Medin (Faculty of Natural Sciences and Mathematics, University of Montenegro) -
36
Design and Characterization of Planar-Circular Composite 3D-Trench Silicon Detector
This study presents a novel planar-circular composite 3D trench silicon detector. The device has already been fabricated on a p-type epitaxial layer via an 8-inch CMOS-compatible process at IMECAS. Comprehensive characterizations based on TCAD simulations, electrical measurements, and the transient current technique (TCT) verify that the optimized composite structure achieves uniform electric field distribution across the active region and favorable overall performance. The fabricated device features a leakage current of 100 pA, a capacitance of 0.65 pF, and time resolution of 50 ps. This high-performance detector with good fabrication compatibility serves as a promising candidate for high-precision 4D tracking and ultra-fast timing measurements in advanced radiation detection systems.
Speaker: Huimin Ji (the Institute of Microelectronics of Chinese Academy of Sciences) -
37
DJ-LGAD RD50 project report
A report on the DJ-LGAD and adaptive gain layer RD50 project
Speaker: Dr Simone Michele Mazza (University of California,Santa Cruz (US))
-
32
-
15:45
Coffee Break
-
WG7 (WP4)
-
38
IntroductionSpeakers: Dominik Dannheim (CERN), Fabian Huegging (University of Bonn (DE)), Giovanni Calderini (LPNHE-Paris, Centre National de la Recherche Scientifique (FR))
-
39
In-house Flip-Chip Hybridisation Updates
Hybrid pixel detector developments strongly rely on fast, reliable and cost-effective interconnection technologies, particularly during prototyping phases. Conventional wafer-level hybridisation techniques provide excellent performance but require complex industrial infrastructures, long turnaround times and high production costs. These constraints limit rapid design iterations and reduce accessibility for High-Mix Low-Volume (HMLV) R&D projects and detector developments based on Multi-Project-Wafer submissions.
Within the CERN EP R&D programme and the DRD3 collaboration, several flexible in-house single-die hybridisation solutions have been developed for the pixel-detector community, complementing existing industrial wafer-level processes. These methods combine different bump formation techniques, including Electroless Nickel Immersion Gold (ENIG) plating and gold-stud deposition, with adhesive-based bonding approaches such as Anisotropic Conductive Films (ACF), Anisotropic Conductive Pastes (ACP), and non-conductive adhesives. The techniques offer fast turnaround, reduced costs and high adaptability to a broad range of detector geometries and pitches, enabling prototype evaluation without access to industrial-scale hybridisation facilities.
This contribution provides an update on these developments. Recent improvements have demonstrated hybridisation capabilities down to 25 µm pitch, with interconnection yields of up to 99% on dedicated test structures. Ongoing studies include irradiation campaigns aimed at validating the long-term robustness of the interconnections under realistic experimental conditions.Speaker: Dr Ahmet Lale -
40
First results from irradiation tests of ACA-bonded chain devicesSpeaker: Yahya KHWAIRA
-
41
First preliminary results on bonding activities at INFN Cagliari [remote]
The development of advanced IC packaging, such as hybridization in hybrid pixel detectors, for high-energy physics (HEP) typically requires complex bonding techniques that are highly demanding in terms of both time and costs. This challenge is particularly pronounced in single-die R&D, where bonding only a few dies is disproportionately high in terms of costs and time.
As a low-cost and faster alternative to traditional bump bonding, Anisotropic Conductive Films (ACF) have become increasingly viable. Development of this technology in HEP has been ongoing for the past decade, notably within CERN, the University of Geneva and the DRD-3.
Recently, as part of the INFN PNRR project ETIC, a new microelectronics assembly facility became operational at INFN Cagliari. Housed within an ISO 5 cleanroom, the facility's core instrument is a new modular flip-chip die bonder capable of delivering up to 1000 N of bonding force and temperatures up to 450°C.
Current bonding tests are being conducted using TimeSPOT-1 first generation 4D tracking readout chips (ROCs) and new IGNITE-32 ROCs. The bonding film, provided by 3TFrontiers, is a next-generation ACF featuring position-sensitive particles and a thickness of under 10 micrometers. In parallel, a second fabrication effort, based on the IGNITE-64 ROC at CERN and the University of Geneva, is currently undergoing testing at INFN Cagliari.
This contribution will present preliminary results from both bonding and testing activities and provide an overview on future developments.
Speaker: Angelo Loi (Universita e INFN, Cagliari (IT)) -
42
In-house indium bumping and bonding for fine-pitch hybrid pixel detector R&D [remote]
Hybrid pixel detector R&D requires flexible interconnection technologies that can support small-volume prototyping, rapid design iterations and increasingly fine pixel pitches. Indium bump bonding is a well-established approach in HEP detector production and remains attractive as pitches decrease, offering a complementary route to adhesive-based bonding techniques such as ACF.
This contribution presents a proposal to develop an in-house chip-level indium bumping and bonding capability for pixel detector hybridisation.
The proposed work would focus on establishing a reproducible process baseline for indium bump formation and subsequent thermocompression bonding, using existing test vehicles and process infrastructure to guide the development.The aim is to establish an early proof-of-principle capability for fine-pitch indium interconnects (Technology Readiness Level 3), complementing the ongoing ACF developments, expected to reach TRL 6 within the next year.
The contribution will also outline how interested partners could support and contribute with test assemblies addressing their respective application needs.Speaker: Mateus Vicente (Geneva Connection Technologies) -
43
Nanowire-Based Thermal Interconnects for Enhanced Thermal Management in High-Density Silicon Pixel Modules [remote]
The increasing integration density of silicon pixel sensors, together with emerging applications such as module-level power conversion and enhanced on-detector signal processing, significantly raises the demand for advanced thermal management solutions. Efficient heat removal at the module level is becoming a critical requirement for ensuring stable and reliable operation. In this work, we demonstrate the use of nanowire-based interconnects to improve the thermal coupling between a silicon die and a heat sink, achieving superior performance compared to conventional thermal interface materials such as conductive pastes.
Two bonding approaches for nanowire integration, adhesive bonding and sintering, are presented and systematically compared in terms of thermal efficiency, bonding process requirements, and bonding process demands. The advantages and constraints of each method are discussed, highlighting their suitability for different integration scenarios. Furthermore, we demonstrate that these bonding technologies can be employed not only to enhance thermal conduction but also to mechanically mount silicon pixel sensors onto supporting structures. This dual functionality provides both improved heat dissipation and robust mechanical stability using minimal material.
Together, the presented thermal and mechanical bonding strategies offer a scalable pathway to enhance module-level thermal stability, supporting the performance and longevity of future high-density detector systems and related applications.Speaker: Julian Weick (CERN) -
44
All-Silicon Modules - RDL layers for thin CMOS chips
Silicon Pixel Detectors are an essential part of most modern tracking systems for high energy physics as they can fulfill requirements of high spacial and time resolution, feasible power consumption and relatively low material budget. To cover large areas in the detector volume individual chips are glued together to create modules. These modules are easier to assemble to full tracking systems, than what would be possible if all chips had to be installed individually, however, gluing, additional flex PCBs, cooling and support structures, and also structural silicon can introduce significant amounts of material.
To reduce the material budget of tracking detectors as far as possible, a new concept of module-building is investigated. By post-processing monolithic chip wafers, redistribution layers (RDL) can be build on top of the chips for electrical connections to 4 chips in a row. By using low power monolithic chips air cooling can be feasible and mechanical support is not necessary for thin ladder structures of up to 15 cm in length with thicknesses around 200 micron.
This talk will discuss concepts, look into prototype production, and discuss measurements and simulations of high speed differential lines for module-sized RDL.
Speaker: Andreas Ulm
-
38
-
11th collaboration board meeting: https://indico.cern.ch/event/1701087/Convener: Dr Giulio Pellegrini (Centro Nacional de Microelectrónica (IMB-CNM-CSIC) (ES))
-
-
-
WG2 (WP2): Hybrid silicon technologies
-
45
First results on LGAD/nLGAD detector performance in laser-driven proton-boron (p-B) fusion plasma diagnostics
In this contribution, we report on the use of Low Gain Avalanche Detectors (LGADs) as fast diagnostics in a high-intensity laser-driven proton–boron (p–B) fusion experiment conducted at the ELI-ERIC facility in the Czech Republic, organized under the PROBONO COST Action (CA21128).
p-type deep-multiplication-layer LGAD (dLGAD) and n-type LGAD (nLGAD) sensors from IMB-CNM production were used as time-of-flight (ToF) diagnostics to detect prompt X-ray emission and charged particles produced during laser–target interactions. The detectors successfully resolved the prompt X-ray flash and subsequent particle arrivals, allowing reconstruction of particle energies in the MeV range, possibly originating from protons.
Post-experiment electrical characterization shows no measurable degradation of detector gain or leakage current compared to pre-irradiation values. These results represent the first application of LGAD technology in a p–B fusion experiment and demonstrate its potential as a ToF diagnostic in high-flux laser–driven plasma environments.
Speaker: Milos Manojlovic (Consejo Superior de Investigaciones Cientificas (CSIC) (ES)) -
46
A novel LGAD design with continuous gain layer: MARTHA
MARTHA (Monolithic Array of Reach-Through Avalanche Diodes) is a novel LGAD concept developed for future high-granularity timing detectors requiring simultaneous precision timing and high spatial resolution, as envisioned for next-generation collider experiments such as FCC-ee. By introducing an additional low-doped n-layer between the n$^{+}$ contact and the gain layer, the electric field distribution is sufficiently reduced to allow sensor pixelation without segmentation of the gain layer itself. As a consequence, MARTHA provides a true 100% fill-factor architecture while preserving intrinsic gain properties.
The MARTHA concept is currently in the proof-of-principle phase. So far, eight wafers featuring three different gain-layer implementations have been designed and produced by the Halbleiterlabor der Max-Planck-Gesellschaft (HLL-MPG) on 450$\mu$m thick substrates. The initial substrate thickness was chosen to address requirements from photon-science applications; future productions will optimize the implant design to be produced on thinner wafers, to achieve timing performance competitive with high-energy physics applications.
First characterization studies have been performed using Transient Current Technique (TCT) measurements and particle-beam tests. The voltage dependence of the gain and spread across the wafer of the three MARTHA variants was investigated using a 1060 nm infrared laser system. Stable gains in the range 20-80 are obtained, which are larger than for typical LGAD (G~10-20).
In addition, the timing performance of dedicated diode structures was studied during a beam campaign at the DESY II test beam facility. A timing resolution of 281 ps, after jitter subtraction, was obtained, in agreement with expectations for LGAD sensors of this thickness.
Furthermore, strip sensors with a pitch of 100$\mu$m were investigated using a dedicated readout system at the DESY II test beam facility with 5 GeV electron beams, to determine the MIP detection efficiency in the inter-strip region. These measurements provide a first validation of the MARTHA concept for highly segmented detector geometries.
This contribution presents the MARTHA sensor concept together with the first experimental characterization results from laboratory and test-beam measurements.Speaker: Esther Constanze Wais (Hamburg University (DE)) -
47
Test beam results and laser studies on AC-LGADs with transformer-based ML methods
Resistive Silicon Devices (RSDs), particularly AC-coupled Low Gain Avalanche Diodes (AC-LGADs), open the path for picosecond-level space and time (4D) tracking in high-energy physics (HEP) experiments such as those at the Large Hadron Collider (LHC), Electron-Ion Collider (EIC), and future (lepton) collider facilities. These sensors combine the fine spatial resolution of segmented detectors with the excellent timing performance of LGADs, achieving nearly 100% fill factor. Unlike conventional detectors, typically structured as linear strip arrays (1D) or pixel matrices (2D), RSDs offer a highly flexible geometry for readout pads, allowing for optimisation based on experimental demands.
When ionizing radiation interacts with these sensors, the generated charge spreads beyond adjacent pixels. This broad charge sharing, while beneficial for interpolation-based resolution enhancement, is complicated by reduced signal amplitudes and Landau fluctuations on pixels farther from the true hit location. To address these challenges, we study pixelated AC-LGADs fabricated at Brookhaven National Laboratory with different pad geometries, including square and triangular configurations with a 500 μm × 500 μm pitch, and analyse their impact on spatial resolution.
In contrast to previous studies, we leverage full-waveform information from each readout channel and utilise transformer-based architectures and RNNs to infer the full waveforms of the readout pads, given the hit’s position and AC-LGAD structure, thereby reconstructing the hit position. The higher precision achieved by the classical charge-imbalance and geometry-based matrix inversion methods is leveraged by the amount of information processed by the networks, such as identifying optimal trade-offs between spatial granularity and data volume. Initial studies on Transient Current Techniques are used as inputs to further refine the algorithms with particle beams at SPS, where Landau fluctuations challenge the readout. We report on the latest results from both TCTS and test-beam data analysis, as well as the latest geometry-independent models.
Speakers: Gaetano Barone (Brown University), Leena Diehl (University of Zurich (CH)), Lixing Wang (Brown University) -
48
Research on Silicon Pixel Sensors for X-ray Free Electron Lasers
X-ray free-electron lasers (XFELs) feature ultra-high brightness, ultrashort pulses and ultra-high repetition rates, and serve as advanced large scientific facilities for exploring material structures and ultrafast dynamic processes of matter. The Shanghai High-Intensity Hard X-ray Free-Electron Laser Facility (SHINE), China’s first hard X-ray free-electron laser facility currently under construction, is soon to be commissioned. Its ultrafast material structure characterization experiments require a matched ultrafast imaging detection system, and the supporting X-ray detection system with ultra-high frame rate and large dynamic range is currently under development. As core photoelectric conversion devices for the detection system, silicon pixel sensors face challenges from high-brightness and high-repetition-rate X-ray pulses. They are required to have high operating voltage and low leakage current to ensure fast charge collection and enhance detection stability. To meet the aforementioned core requirements of high voltage and low leakage current, this paper presents an in-depth study on the structural design and process optimization of silicon pixel sensors. A multi-guard ring structure is designed to optimize the surface electric field distribution, thereby effectively improving the device breakdown voltage. Meanwhile, precise modulation of the ion doping process is carried out to optimize doping concentration and depth and reduce device leakage current, achieving synergistic performance improvement through structural and process optimization. In addition, photolithography stitching technology is adopted to overcome the fabrication difficulties of large-array sensors. Relying on the 8-inch integrated circuit pilot platform of the Institute of Microelectronics, Chinese Academy of Sciences, two silicon pixel sensors with different pixel sizes have been successfully fabricated, with pixel dimensions of 200μm×200μm and 100μm×100μm and array scales of 128×512 and 256×1024, respectively. Performance test results show that the pixel cell breakdown voltage of both sensors exceeds 1000 V, and the dark current is below 3pA/pixel@500V, fully meeting the core performance specifications of the SHINE detection system.
Speaker: Gaobo Xu (Institute of Microelectronics of Chinese Academy of Sciences) -
49
Resonant-Cavity-Enhanced GOI PIN Photodetectors with Integrated DBR Structures for High-Performance SWIR Detection
Short-wave infrared (SWIR) photodetectors with high responsivity and low dark current are highly desired for applications in optical communication, infrared imaging, and integrated photonic systems. In this work, resonant-cavity-enhanced (RCE) Ge-on-insulator (GOI) PIN photodetectors incorporating distributed Bragg reflector (DBR) structures were designed, fabricated, and experimentally investigated.
The proposed devices employed periodic SiO2/Si DBR structures embedded beneath the Ge absorption layer to enhance optical confinement and improve light–matter interaction within the resonant cavity. Device structures with different DBR periods were systematically analyzed using Sentaurus TCAD simulations and optical modeling. Simulation results revealed that the 4-period DBR structure provided stronger optical field enhancement and higher reflectivity compared with the 2-period structure, leading to improved carrier generation efficiency at SWIR wavelengths.
Based on the optimized design, RCE GOI PIN photodetectors were fabricated using a CMOS-compatible process. Electrical and optical characterizations demonstrated that the 4-period DBR device achieved responsivities of 0.86 A/W at 1310 nm and 1.02 A/W at 1550 nm under −1 V bias, while maintaining a low dark current of 3.21 nA. Compared with the 2-period DBR device, the responsivity at 1550 nm was enhanced by approximately 35%. In addition, distinct oscillatory spectral-response characteristics further confirmed the resonant-cavity enhancement effect. Monolayer graphene was also integrated onto the device surface to further improve carrier collection efficiency, resulting in additional responsivity enhancement at SWIR wavelengths.
These results demonstrate that integrating DBR-assisted resonant-cavity structures with the GOI platform is an effective approach for developing high-performance, CMOS-compatible SWIR photodetectors for next-generation silicon photonic and infrared imaging applications.Speaker: jiahan Yu (Institute of Microelectronics, Chinese Academy of Sciences)
-
45
-
10:10
Cofee break
-
WG1 (WP1): CMOS technologies
-
50
Introduction to WG1/WP1 sessionsSpeakers: Eva Vilella Figueras (University of Liverpool (GB)), Heinz Pernegger (CERN), Jerome Baudot (IPHC - Strasbourg)
-
51
Latest TCAD Results for the Optimization of Internal-Gain CACTUS Sensors in the 150 nm LFoundry Process
The CACTUS (CMOS ACtive pixel Timing Sensor) project aims to develop radiation-hard monolithic sensors with excellent timing performance in a standard CMOS process. The latest prototype, MiniCACTUS-v2, has achieved timing resolution in the 50 ps regime using drift-only depleted CMOS sensors fabricated in the 150 nm LFoundry HV-CMOS process on high-resistivity p-type substrates.
To further improve the timing performance towards the sub-30 ps regime and enable smaller pixel pitches, an internal gain layer (GL) has been introduced. A first proof-of-concept generation of monolithic sensors with intrinsic gain, CACTUS-GL, has been fabricated in the same LFoundry process and is currently under characterization. This production includes several test structures with different gain-layer concentrations and termination layouts, and preliminary measurements with a beta source and an infrared laser have already demonstrated signal amplification.
Based on these first results, we present TCAD optimization studies for the next CACTUS-GL submission. The study explores variations in phosphorus and boron doping concentrations, as well as the impact of gain-layer termination on the electric field distribution, breakdown behavior, and charge multiplication. Simulations were carried out for 150 μm high-resistivity (HR) and 30 μm epitaxial (epi) substrates. IV, CV, and transient simulations, including the response to a minimum ionizing particle (MIP), were used to evaluate gain and signal formation for 0.5 × 0.5 mm², 0.5 × 1 mm², and 1 × 1 mm² device geometries. The results guide the optimization of both the sensor layout and the front-end electronics in the second CACTUS iteration with an internal gain layer.
Speaker: Juan Ignacio Drovandi (Consejo Superior de Investigaciones Cientificas (CSIC) (ES)) -
52
A fully digital TDC for the CACTUS monolithic timing detector
MiniCACTUS is a series of large collecting electrode monolithic sensor prototypes developed for precision timing applications in future large-area timing detectors for high-energy physics experiments. These have been fabricated with a 150 nm HV-CMOS process from LFoundry. The most recent prototype, MiniCACTUSV2, incorporates several pixel sizes, ranging from 1×1 mm2 down to 500×500 μm2. The later pixels show a timing precision of 50 ps measured in testbeam.
The analog readout electronics of MiniCACTUS prototypes include a preamplifier and a discriminator with a DAC for fine tuning the threshold, but lack of TDCs to measure Time of Arrival (ToA) and Time over Threshold (ToT). In order to achieve a real monolithic timing detector, future prototypes will incorporate a TDC.
This contribution will present a fully digital high-resolution TDC for next MiniCACTUS prototypes. It is based on a digital untuned oscillator built with 64 inverters providing a time resolution below 10 ps according to the bin size. The calibration is performed with the wave-union technique. The TDC allows sharing the same oscillator to measure the ToA and ToT on multiple pixels.Speaker: Raimon Casanova Mohr (IFAE - Barcelona (ES)) -
53
Recent Testbeam Results of MiniCACTUSV2 and Novel Gain-Layer Sensor Prototypes
MiniCACTUS is a series of large fill-factor monolithic sensor prototypes developed for precision timing applications in future large-area timing detectors for high-energy physics experiments. The devices are fabricated in the 150 nm LFoundry HV-CMOS technology on high-resistivity p-type substrates, where charge collection is achieved through a deep n-well electrode.
The most recent prototype, MiniCACTUSV2, incorporates several pixel geometries with implant dimensions ranging from 1$\times$1 $mm^{2}$ down to 50$\times$50 $\mu m^{2}$. Dedicated analog front-end electronics and discriminator stages are implemented at the column level to evaluate the performance of the different sensor layouts. The sensors have been processed for backside biasing and produced with active thicknesses of 150, 175, and 200 µm.
In parallel with the studies of standard sensor structures, LFoundry has recently produced the first diode prototypes incorporating a gain-layer. These devices have been fabricated both on 150 µm thick high-resistivity substrates and on 30 µm epitaxial silicon layers.
The timing performance and detection efficiency of both MiniCACTUS and gain-layer devices have been evaluated during the last two DRD3 beam-test campaigns at the CERN SPS using high-energy pion beams. This contribution summarises the beam-test results of the MiniCACTUSV2 prototypes and presents the first characterisation measurements of the newly developed gain-layer sensors.
Speaker: Stefano Terzo (IFAE Barcelona (ES)) -
54
Infrared and 90Sr characterization of LFoundry 150 nm test structures with intrinsic gain for the Cactus development line
The Cactus line of sensor demonstrators is focused on the investigation of timing performance that can be reached with non amplified sensors, as well as with sensors with intrinsic gain.
Test structures featuring an integrated gain layer in the form of a buried PN junction have been submitted as part of an MPW run in 2024 in the Lfoundry 150 nm LF15A process. Four wafers have been produced in total, with two different doping parameters for the gain layer. Two wafers with high resistivity substrate, and two epi wafers with a thin (30 microns) high resistivity epitaxial layers.
Detailed signal height and gain measurements with infrared light pulses as well as with 90Sr beta decays will be presented. These results give directions for further optimisation of the concept. Perspectives for detailed pulse shape studies and assessment of the response uniformity of this type of sensor will also be mentioned.
Speaker: Prof. Philippe Schwemling (Université Paris-Saclay (FR)) -
55
Recent results of the CASSIA project
The CASSIA (CMOS Active SenSor with Internal Amplification) project is focused on developing monolithic active pixel sensors (MAPS) with internal signal gain in the Tower 180nm CMOS process.
An internal amplification enables the simplification of the in-pixel electronics while simultaneously improving the signal to noise ratio for radiation hardness and offering the potential for excellent timing performance for future 4D tracking applications.
This presentation will focus on measurements of the first prototype sensors (CASSIA1) that have been fabricated to demonstrate the feasibility of the gain layer implementation into the Tower Semiconductor 180nm CMOS process. Currently the second iteration of a new prototype (CASSIA2) is in production, which implements the in-pixel electronics alongside the sensor structure with gain, to operate them in either low-gain (LGAD) or high-gain (SPAD) mode.In this presentation charge collection, gain and time resolution measurements utilising the Transient Current Technique will be presented, comparing the four different matrices with varying gain-layer designs for sensors produced in the epitaxial and in the Czochralski process. Additionally, the waveforms are evaluated to investigate the effects of the different gain layer sizes.
Furthermore, first results of a recent beam test at CERN SPS will be shown to further explore the sensor performance and compare to the TCT results.Speaker: Leena Diehl (University of Zurich (CH)) -
56
The MOSFET Gain Tuning Idea
The need for 4D (fast timing in addition to 3D resolution in space) silicon particle detectors has become very apparent with the introduction of the High-Luminosity (HL) upgrade at the LHC. Timings on the order of tens of picoseconds will allow better reconstruction of the ~200 primary vertices along the beam line in every bunch crossing. Correct association of tracks with primary vertices is particularly difficult closer to the beam axis where the track density is greatest and reconstruction with 3D detectors alone is insufficient. The Marietta Blau Institute for Particle Physics and the National Technical University of Athens are investigating the charge gain behavior of a MOSFET with the aim to operate it as a fast timing silicon sensor. The MOSFET test structures often are integrated on silicon sensor wafers to evaluate p-spray or p-stop isolation implants used between n-type collection electrodes in p-type substrates. Inter-electrode isolation is a critical parameter in highly segmented silicon detectors, directly affecting charge collection, noise, timing performance and radiation tolerance.
The drain–source current as function of gate voltage for different back-side voltages is measured at a fixed drain–source voltage in the linear MOSFET region, and the values of threshold voltage and mobility extracted using the standard MOSFET formulae. From these measurements, depth-resolved doping information is reconstructed through a dedicated analysis framework that accounts for localized space-charge effects and electric-field screening introduced by the p-spray or p-stop implants. In addition the presentation contains TCT characterisation results where the MOSFET is illuminated by a focused near-infared laser beam which is perpendicular the sensor surface. The two electrodes source and drain are connected seperately to the input of transimpedance amplifiers. Analyzing the current pulse shapes, the charge collection profile perpendicular to the electrodes is extracted.
The MOSFET used for this study fabricated with a continuous 𝑝+-implant (p-spray) under the gate. It was produced on Magnetic Czochralski silicon doped with ≈ 3.5 × 10$^{12}$ cm$^{−2}$ of boron and ⟨100⟩ crystal orientation.
Speaker: Ioannis Kopsalis (National Technical Univ. of Athens (GR))
-
50
-
Social Events: Lunch
-
Social Events: Visit to Bucharest & Dinner
-
-
-
WG6 (WP3): WBS Sensors (1)
-
57
Introduction to WG6Speakers: Alexander Oh (The University of Manchester (GB)), Tao Han (University of Wisconsin), Xin Shi (Chinese Academy of Sciences (CN))
-
58
Developments of 4H-SiC sensors for Timepix4
The wide bandgap 4H-SiC semiconductor material exhibits several intrinsic properties, including excellent radiation hardness, thermal stability, and high breakdown voltage, making it a promising candidate for deployment in high-radiation environments. Recent advances in its industrial-scale production have further enhanced its attractiveness for high-energy physics applications. This contribution presents an overview of the development and characterization of 4H-SiC-based sensors produced by the onsemi company based in the Czech Republic. The study includes the evaluation of 4H-SiC PN diodes and Low Gain Avalanche Detectors (LGADs) featuring an internal charge multiplication layer. Electrical characterization covers the dependence of reverse leakage current and bulk capacitance on the applied depletion voltage, together with internal gain measurements using UV light sources. Building on these laboratory measurements, the sensors were installed at the CERN SPS for a first test beam campaign. Early results demonstrate the detection of minimum ionizing particles and characterize the performance of the LGAD samples under beam conditions. The next phase of the programme will extend this work to pixelated 4H-SiC detectors bump-bonded to the Timepix4 ASIC, providing spatially resolved and time-tagged measurements of charged particle hits in the near future. In addition, characterization studies with x-rays are planned at Sirius, the Brazilian Synchrotron Light Laboratory. This facility offers x-rays with tunable energies between 8 and 30 keV with a beam size of 200 x 200 nm². The results obtained so far, together with the planned studies, will provide new insights into the radiation hardness of 4H-SiC devices and underscore their potential for future use in demanding environments typical for next-generation high-energy physics experiments.
Speaker: Floris Patrick Jan Fassin (University of Groningen (NL)) -
59
Time Resolution of a Novel Ultra-fast Graphene-Optimized 4H-SiC detector
Silicon carbide detectors exhibit good detection performance and have been studied for various detection applications. However, in some applications the presence of metal is undesirable, such as low-penetration particle detection, UV light detection and medical dosimetry. A graphene-optimized 4H-SiC detector has been fabricated not only meet the aforementioned detection requirements, but also shorten the signal rise time and time resolution. Its electrical properties and time resolution performance of β particles performance are reported. The effective doping concentration of lightly doped 4H-SiC epitaxial layer is about 4.6 × 1013cm−3, approaching the limit of the lowest doping level by the SiC epitaxial growth technique. TCT measurements demonstrate that graphene-optimized 4H-SiC PIN improves the time resolution consistency, reducing the time resolution from 38.1 ps (reference ring electrode 4H-SiC PIN detector) to 21.2 ps (graphene-optimized 4H-SiC PIN) at the maximum scanning distance. The TCT test demonstrated that the time resolution stability of the graphene-optimized 4H-SiC detector was 87% higher than that of the ring electrode detector. ⁹⁰Sr source tests further confirm the advantage of the graphene optimized ring electrode silicon carbide detector, which achieves a time resolution of 58.0 ps, versus 96.0 ps for ring electrode silicon carbide detector. Experimental results indicate that time resolution performance of graphene-optimized 4H-SiC PIN exhibit good stability. And the time resolution stability at different positions of the graphene-optimized detector has uniform timing performance.
Speaker: Congcong Wang (Chinese Academy of Sciences (CN)) -
60
Development of the SICAR 4H-SiC Radiation Detector
This abstract reports on the design, fabrication, and characterization of the SICAR 3 4H SiC low gain avalanche detector (LGAD) implemented on a 350 nm SiC MOSFET process platform. Unlike previous SICAR 1 and SICAR 2 generations that relied on epitaxy defined structures, the SICAR 3 device employs an ion implantation based process to form the gain layer, junction termination extension (JTE), and p⁺⁺ contact layer. The edge termination is realized with a JTE assisted field plate, replacing the earlier mesa plus field plate design. PIN diodes, Schottky diodes, and LGADs were fabricated on the same wafer, which consists of a low resistivity p type 4H SiC substrate, a 70 μm thick N⁻ epitaxial layer (1×10¹⁴ cm⁻³), and implanted regions activated above 1500 °C.
Electrical characterization shows that the selected LGAD device has a higher reverse leakage current (approximately 10⁻⁵ A at 1000 V) than the PIN device (approximately 10⁻⁹ A). Capacitance–voltage measurements reveal a distinct gain layer depletion feature at 120–130 V. Charge collection measurements using a ⁹⁰Sr source demonstrate that, relative to the PIN reference device, the LGAD achieves a charge gain of approximately 10 at high reverse bias. Preliminary timing measurements, after subtracting the reference contribution, yield a detector time resolution of 60 ± 5 ps at a reverse bias of 400 V. These results verify the basic feasibility of forming a 4H SiC LGAD multiplication structure by MOSFET process platform.
Speaker: Xiyuan Zhang (Chinese Academy of Sciences (CN)) -
61
Characterization of 4H-SiC implanted LGADs after 23 MeV Proton Irradiation
The demand for radiation-hard 4D detectors capable of simultaneous high-precision timing and spatial resolution is driving the investigation of 4H-Silicon Carbide (4H-SiC) as a robust alternative to silicon. While 4H-SiC offers superior thermal stability and radiation tolerance, its wide bandgap and current epitaxial thickness limits necessitate the use of internal charge multiplication. This work presents an extensive performance evaluation of 4H-SiC LGADs and PN junction diodes fabricated by Onsemi on 6-inch wafers (50 $\mu$m epitaxial layer, $\text{n} \approx 5 \times 10^{13} \text{ cm}^{-3}$). The devices were subjected to 23 MeV proton irradiation, covering five fluences from $1.3 \times 10^{14}$ to $2 \times 10^{15} \text{ p/cm}^2$. They have been characterized in terms of current–voltage I-V and capacitance–voltage C-V measurements. Furthermore, the impact of temperature (up to 200°C for I-V/C-V) is investigated to evaluate defect dynamics and the operational stability of 4H-SiC LGADs in extreme environments.
Speaker: Francesco Moscatelli (IOM-CNR and INFN, Perugia (IT)) -
10:25
Coffee break
-
57
-
WG5
-
62
WG5 Introduction
-
63
Laser based technique for shot noise measurement
Presentation of the technique for shot noise measurement using laser induced current.
Speaker: Marko Puklavec (Jozef Stefan Institute (SI)) -
64
Transformer-Based ML Reconstruction of Position and Time in SiC AC-LGAD Sensors
SiC-LGAD sensors are promising candidates for timing and tracking detectors at future colliders. However, accurate position and time reconstruction can be challenging with analytical models when signal formation deviates from idealized assumptions. We present studies on SiC AC-LGAD using transformer-based machine learning models that process the full time-series waveform from the sensor readout. The models are trained with Transient Current Technique (TCT) laser measurement data, allowing the network to learn the correlation between waveform features and interaction position and time. Compared with a baseline analytical reconstruction, this approach achieves improved position and time resolution, demonstrating the potential of ML-based reconstruction for advanced SiC-LGAD tracking.
Speaker: Chengxi Yang (University of California Berkeley (US)) -
65
Effects of temperature and optical excitation on the spectroscopic properties of ion-irradiated 4H-SiC detectors
Advanced technologies such as nuclear fusion reactors, high-energy physics facilities, and space applications require radiation detectors capable of reliable operation under extreme conditions. In particular, the detection of 3.5 MeV alpha particles in future fusion devices like ITER demands high radiation hardness, thermal stability, and good spectrometric performance. 4H-SiC stands out due to its wide bandgap, high thermal conductivity, and exceptional resistance to radiation damage and high temperatures. Radiation hardness tests at room temperature, up to fluences of 5×10¹¹ ions/cm², revealed progressive degradation of charge collection efficiency (CCE). This degradation is caused by intrinsic and radiation-induced trapping centers (defects and impurities) that capture charge carriers and impair detector performance [1]. In this work, we present an experimental study carried out at the ion beam microprobe of the National Accelerator Center (CNA, Spain), investigating the influence of optical excitation on the spectroscopic response of 4H-SiC detectors damaged by 3.5 MeV alpha particles at different temperatures. Nine regions (100×100 µm²) were irradiated with 3.5 MeV alpha particles at fluences between 1×10¹¹ and 1×10¹³ ions/cm², at room temperature and at 400°C. The irradiated areas were subsequently characterized at room temperature by ion beam induced charge measurements to assess the effect of radiation-induced defects on charge carrier transport and collection. Controlled optical excitation with a blue LED was then applied to study its effect on CCE. The results demonstrate that optical illumination produces significant improvement in the CCE, particularly in regions exhibiting increased trap density, demonstrating that optical illumination represents a simple and cost-effective approach to reduce radiation damage effects.
References
[1] Jiménez-Ramos, M.C., et al. (2020). “IBIC analysis of SiC detectors developed for fusion applications”. Radiation Physics and Chemistry, 177, 109100. https://doi.org/10.1016/j.radphyschem.2020.109100
Speaker: Mauricio Rodriguez Ramos (Centro Nacional de Aceleradores (CNA). University of Seville.) -
66
Research on Alpha Detection of Hydrogen-Boron Reaction Based on SiC Detector
The hydrogen-boron fusion reaction is a promising candidate for future clean fusion energy. This work develops a silicon carbide (SiC) detector system for detecting alpha products from the hydrogen-boron reaction, focusing on response characteristics, energy resolution, and radiation hardness.
A single-channel SiC detector (5 mm × 5 mm with guard ring) was fabricated. Tests with an alpha source in air achieved energy resolutions better than 10% at 100 V and 9% at 500 V. At the IMP CAS test platform, a 200 keV proton beam was used to bombard a boron target to generate the hydrogen-boron reaction. The SiC detector clearly resolved the 5.8 MeV high-energy alpha peak with an energy resolution of ~4%, and also recorded alpha signals in the 3–4 MeV range. Furthermore, no significant change in IV characteristics was observed under irradiation doses from 1e12 to 1e16/cm².
These results demonstrate that the SiC detector has the potential for effective alpha product detection in harsh fusion environments, offering a feasible solution for online monitoring of hydrogen-boron fusion reaction intensity.Speaker: Suyu Xiao (Shandong Institute of Advanced Technology, China) -
67
A General Purpose High-Frequency Readout BoardSpeaker: Stefan Gundacker (Austrian Academy of Sciences (AT))
-
68
DiscussionSpeaker: Prof. Ivan Vila Alvarez (Instituto de Física de Cantabria (CSIC-UC))
-
62
-
Social Events: Lunch
-
WG1 (WP1): CMOS technologies
-
69
DMAPS for space applications
DMAPS can become a disruptive technology for miniaturized space instrumentation. Developments studied in the context of DRD3 collaboration can find applications in proton, ion and electron flux measurement problems encountered in heliophysics, and radiation monitoring - protection in the space environment. We will present simulation results supporting the inclusion of DMAPS in such instruments. We have developed DMAPS ASICs to a certain extent for such applications, and we will discuss the lessons learned.
Speaker: Haris Lambropoulos (National and Kapodistrian University of Athens) -
70
Monstera Large tracking detector volumes
The next generation particle physics experiments requires scalable technologies at moderate prices and at highest possible integration levels to reduce system complexity. The Monstera project investigates fully integrated strips developed in LFoundry 150nm HV-VMOS, based on previous successful testing of passive strips. The design profits from the exiting readout and configuration scheme that has been implemented for the LHCb Mighty tracker upgrade. The contribution will recap on previous strip testing, introduce
the current design status within the shared DRD3 submission and give a preview on planned tests.Speakers: Ingrid-Maria Gregor (DESY & Bonn University), Lennart Huth (Deutsches Elektronen-Synchrotron (DE)) -
71
Development Status & Plans of Serial Powering at IHEP
The drive for higher spatial resolution and larger tracking coverage in high-energy physics has led to silicon pixel detectors spanning several square meters, integrating tens of thousands of readout units. Conventional parallel powering, which supplies each module via separate cables, results in a proliferation of cabling that dramatically increases the material budget, exacerbates multiple Coulomb scattering, degrades tracking performance, and introduces severe engineering challenges. To fundamentally reduce cable count and minimize material mass, serial powering—connecting multiple modules in series driven by a constant-current source—has emerged as a critical enabling technology. This approach reduces power cables from quadratic to linear scaling with the number of modules.
Although not yet used in operational experiments, serial powering has been adopted as the baseline architecture for the HL-LHC ATLAS ITkPixel and CMS Inner Tracker upgrades, with LHCb Upgrade II pursuing related R&D. Building on the LHCb roadmap, we are conducting domestic research using HV-CMOS pixel sensor chips. Our efforts focus on ATLASPix3-based Shunt-LDO (SLDO) tests, including probe card design, bare chip characterization, and PCB-level validation. Concurrently, we are evaluating COFFEE and CHiR chips with integrated SLDO designs. Future plans include probe card improvements to optimize load values and core chip connections, ATLASPix-based module prototyping using a 1×4 test board designed on a Quad flex (limited to fewer than nine chips), and CHiR-based tests upon chip availability. Through these systematic steps, serial powering demonstrates broad applicability and strategic importance for next-generation experiments, offering a critical solution to the material and complexity challenges of ultra-large-scale silicon tracking systems.
Speaker: Hui Zhang (Institute of High Energy Physics) -
72
Early results with the asynchronous architecture of SPARC
SPARC (Sensor Pixel Asynchronous Readout CMOS) is a small MAPS prototype designed in a 65 nm CMOS technology to test and validate a new asynchronous logic to read pixel matrices. Based on a tree of asynchronous arbiters, this architecture is expected to cope easily with a wide range of hit rates and to deliver fired pixel information in time compatible with few tens ns time-stamping in a power efficient manner.
The SPARC matrix includes 32x28 pixels featuring 25 um x16 um size. The readout architecture explores four different arbiter sizes and time-stamping is provided by a time-to-digital converter outside the matrix.
The first chiplets have arrived mid-April 2026 and have been under tests since then. This contribution will report some very early results on the operability of SPARC functionalities and discuss the test plan.Speaker: Jerome Baudot (IPHC - Strasbourg) -
73
Status of the MANTA project
The MANTA project aims for building a versatile CMOS Monolithic Active Pixel Sensor suited for applications in various silicon trackers. It will provide simultaneously a ~10 µm spatial precision and a fast (1-10 ns) time stamping. This will be reached by complementing i) an asynchronous pixel readout providing the address of the fired pixel within few 10 ns time with ii) a fast pixel OR providing a few ns time information on the same hit. To trade the power consumption in a versatile way against the rate capability, it will be possible to switch-off and/or throttle certain functionalities (e.g. the mentioned pixel OR). Moreover, the sensor will provide in parallel 1 Gbps and 10 Gbps data links, which will allow to cover multiple running and integration scenarios. The presentation will summarise the concept and the status of MANTA.
Speaker: Michael Deveaux (GSI - Helmholtzzentrum fur Schwerionenforschung GmbH (DE)) -
16:00
Coffee break
-
74
Optimizing the MALTA3 readout design for the 65 nm TPSCo node.
MALTA2 is a depleted monolithic active pixel sensor (DMAPS) developed in the Tower Semiconductor 180 nm CMOS imaging process. It features a small collection electrode and achieves a full depletion of the sensitive volume at a low bias voltage of $-6\,\mathrm{V}$. Further development of the MALTA chip aims to satisfy the requirements of the outer layers of the ATLAS Inner Tracker. This requires improving the timing performance (time resolution $< 500\,\mathrm{ps}$), modularization and integration into large-area detector systems ($> 2\times2\,\mathrm{cm}^2$ modules), and radiation hardness ($> 2\times10^{15}\,\mathrm{n_{eq}/cm^2}$ NIEL). In order to cope with these requirements, the design will be adapted to the TPSCo $65\,\mathrm{nm}$ CMOS process. In addition to the analog domain constraints on the chip design, the digital read-out also needs to overcome challenges due to the expected high hit rates ($100\,\mathrm{MHz/cm^2}$). As a result, a redesign of the digital read-out is planned in order to maintain compatibility with both tracking and digital calorimetry in the forward regime.
In order to identify the main challenges and possible improvement paths for the MALTA3 digital read-out, a fast, data-driven simulation was developed. The simulation reproduces a realistic pixel response based purely on measurement input, without relying on detailed knowledge of the underlying fabrication process. Due to its parametric approach, the package is fast and thus particularly useful for larger detector systems and high hit rate environments. Modifications to the sensor’s periphery, mainly in the hit merger, are studied in order to optimize the performance for tracking.
Speaker: Dumitru-Vlad Berlea (Deutsches Elektronen-Synchrotron (DE)) -
75
Status update on OCTOPUS
The OCTOPUS project develops a monolithic pixel sensor in the 65 nm TPSCo process, targeting the vertex-detector layers at a future Lepton Collider.. A single-point resolution of 3 μm, a time resolution in the order of 5 ns, a hit-rate capability of up to 100 MHz/cm², maximal thickness of 50 μm, an average power consumption below 50 mW/cm² are required. Additionally a minimal inactive periphery area and a sensor architecture scalable to a large-area detector system are targeted. To achieve this, detailed simulations based on generic doping profiles are used to optimise the sensor layout and novel readout schemes are developed to process the high data rates with minimal power budget.
The first project stage aims at developing a high-resolution sensors for beam telescopes at DESY and CERN, with relaxed power-consumption (<500 mW/cm²) and timing requirements (100 ns).
The contribution will introduce the project and specifications, present the current status of the chip design and future plans. Additionally, simulation results optimising the sensor geometry will be highlighted.
Speaker: Lennart Huth (Deutsches Elektronen-Synchrotron (DE)) -
76
R&D program proposal focused on the SK hynix 90 nm CIS process for future vertex detector
We propose an R&D program focused on the SK hynix 90 nm CMOS Image Sensor (CIS) process as a dedicated technology option for Future lepton collider vertex-detector MAPS. The near-term goal is to establish and characterize a first generation of reticle-scale pixel-sensor prototypes in this process, including sensor test structures, small matrices, readout architectures, and radiation-tolerance studies. The longer-term goal is to keep the sensor architecture, floorplan, peripheral readout, power distribution, and data-output scheme compatible with future stitched large-area sensors, so that the technology can evolve from proof-of-principle chips to realistic vertex detector in future collider.
Speaker: Zhijun Liang (Chinese Academy of Sciences (CN)) -
77
Development of COFFEE, HVCMOS sensors using 55nm process
High-Voltage CMOS sensors are promising technological candidates for trackers at future circular-electron collider as well as at the LHCb upgrade, due to the fast charge collection and intrinsic radiation hardness. Developed using 55nm CMOS processes, COFFEE seriers sensors aim to deliver a large prototype with high spatial and time resolution. COFFEE3 sensor was a first small prototype with a data-driven readout architecture. First results from COFFEE3 at the DRD3 testbeam will be reported. From previous studies certain features in the current CMOS process would impact the sensor performance in the long term, and improvement in the process is proposed and implemented in a new tapeout. The new MPW, COFFEE-HiRes or simply CHiR, has been submitted early this year and expected to deliver in summer. The process modification and key design features will be introduced in this talk.
Speaker: Yiming Li (Institute of High Energy Physics, Chinese Academy of Sciences (CN))
-
69
-
-
-
WG6 (WP3): WBS Sensors (2)
-
78
Charge Collection and High-Density Ionization Effects in Ultra-Thin 4H-SiC Diodes for FLASH Radiotherapy Dosimetry
Ultra-thin 4H-SiC detectors have demonstrated their potential for real-time dosimetry in FLASH radiotherapy due to their radiation hardness, fast response, and capability to operate at zero bias. In this contribution, we investigate the charge transport and collection properties of partially depleted and non-biased ultra-thin \SI{3}{\micro\meter} 4H-SiC diodes under high ionization density conditions, combining experimental measurements with TCAD Sentaurus and SRIM simulations. Measurements were designed to investigate potential high-density ionization effects, such as recombination-induced charge loss and electric field distortion, as well as to assess device technological features at the nominal operating voltage desired for FLASH (0 V). These effects were investigated by means of IBIC techniques with alpha particles of 1.5, 2.0 and 2.3 MeV, performed at a the CNA 3 MV Tandem accelerator. The results suggested that a non-zero charge collection efficiency was measured even in nominally undepleted regions at zero bias. TCAD simulations and SRIM-based energy deposition profiles support the interpretation of this behavior as a funneling effect, in which the high carrier density generated along the alpha track transiently extends the electric field and enhances charge collection beyond the depletion region.
In addition, a strong interplay between active layer doping and ion LET is identified as a key factor to ensure the linearity of the detector response. In particular, strong funneling effects are observed with TCAD Sentaurus simulations in undepleted 4H-SiC regions when the ion LET reaches or exceeds $\sim$ 100 keV/\SI{}{\micro\meter}.
The combined experimental and simulation evidence of these results provides new insight into charge transport in partially depleted 4H-SiC detectors. Moreover, it also reinforces the potential of IBIC for studying the internal structure and electrical behavior of semiconductor detectors.
Speaker: Jairo Antonio Villegas Dominguez (Universidad de Sevilla (US) - Centro Nacional de Aceleradores) -
79
TPA-TCT Characterization of 4H-SiC PN diodes, LGADs and Strip Sensors
This contribution reports on recent collaborative efforts to characterize 4H-SiC-based detectors using the TPA-TCT method during a three-week campaign at the ELI ERIC facility. The devices under test include large-area pad diodes, segmented strip detectors, and LGADs manufactured at Onsemi in the Czech Republic. The campaign focused on initial commissioning of the TPA-TCT setup using a 400 nm laser, position-resolved charge-collection studies of both fresh and irradiated 4H-SiC devices, and interstrip properties of trench-isolated LGADs.
These measurements constitute a comprehensive TPA-TCT study of the irradiation effects of 24 GeV protons in 4H-SiC detectors, covering devices with and without internal gain over a wide fluence range from 5×10¹² p/cm² up to 5×10¹⁵ p/cm². Measurements on segmented LGADs address charge sharing and interstrip isolation.Speaker: Sebastian Onder (Austrian Academy of Sciences (AT)) -
80
Evaluation of carrier transport in neutron-irradiated 4H-SiC detectros using alpha spectrometry and Angle Resolved-IBIC
This work investigates the neutron-induced degradation of carrier transport in 4H-SiC radiation detectors. Three planar p-in-n diodes developed at IMB-CNM,including a pristine device and two samples irradiated to neutron-equivalent fluences of $4 \times 10^{14} n_{eq}/cm^{2}$ and $1 \times 10^{15} n_{eq}/cm^{2}$, were evaluated under reverse bias voltage. Performance degradation under reverse bias voltage was evaluated using alpha-particle spectrometry. Furthermore, to correlate these effects with depth-dependent transport dynamics, Angle-Resolved Ion Beam Induced Charge (AR-IBIC) was employed to profile the active volume. A drift-diffusion model was fitted to the depth-resolved AR-IBIC measurements to examine the carrier transport properties. This fitting analysis reveals a pronounced asymmetry, demonstrating that holes are significantly more susceptible to trapping by radiation-induced defects than electrons. Ultimately, this drift-diffusion modeling successfully extracts the independent electron and hole drift lengths directly from the AR-IBIC data, establishing a critical benchmark required to validate complementary characterization techniques, such as the Two-Photon Absorption Transient Current Technique (TPA-TCT).
Speaker: Carmen Torres Munoz (Universidad de Sevilla (ES)) -
09:30
Coffee break
-
81
Characterisation of 3D Diamond Detectors Utilising Two-Photon-Absorption Technique
Two-Photon Absorption (TPA) technique has become increasingly popular in recent years as a detector characterisation method because it provides a convenient way to test the response of semiconductor detectors at different positions and under various physical conditions. However, the TPA characterisation of detectors with complex non-transparent 3D electrode geometries is strongly affected by optical shadowing and additional background signals. In this work, a single-crystalline CVD (sCVD) 3D diamond detector containing parallel and twisted square-pixel arrays is investigated using TPA measurements together with a
TCAD-MC simulation workflow. In experiments, we observed a strange Single-Photon-Absorption-like (SPA-like) signal that is not explainable by TPA or SPA processes, and its properties are systematically characterised based on the latest TPA results. Furthermore, empirical TPA signal models, including a charge-depth model and a TPA-TCT waveform model, are established to link the simulation results and experimental measurements. The model is then applied to the investigation of the timing performance in 3D diamond detectors with different pixel structures and to the feasibility study of a neural-network (NN)-based reconstruction algorithm to improve the spatial and timing resolution of 3D diamond detectors.Speaker: Huazhen Li (The University of Manchester (GB)) -
82
Simulation of Diamond Detectors Based on RASER
As a wide-bandgap semiconductor offering advantages such as low dark current, fast response time, high carrier mobility, excellent radiation resistance, and biocompatibility, diamond has recently attracted significant attention in the field of ionizing radiation detection for UV, gamma-rays, X-rays, neutrons, protons, and heavy ions, as well as for detecting charged particles (e.g., electrons, muons, pions) in high-energy colliders such as the Large Hadron Collider. Based on these characteristics, we have collaborated with the RASER organization to carry out simulation-based research on the development of a diamond radiation detector. So far, models related to ohmic/Schottky contacts and defects have been preliminarily established. Moreover, it can simulate important characteristics such as single-particle properties, alpha energy spectra, charge collection efficiency, and energy resolution. Compared with existing experimental results, the simulation results show good consistency.
Speaker: Peiyao Wang (Xidian University) -
83
Potential Using of Organic–Inorganic Hybrid Structures for Detection of Ionizing Radiations
The integration of organic semiconductors into radiation detector technologies has attracted increasing interest due to their compatibility with low-cost fabrication methods, suitability for large-area applications, and inherent mechanical flexibility. Within this framework, the P3HT:ZnO matrix structure offers significant potential by integrating enhanced charge-transport properties with straightforward processability. Such hybrid structures are regarded as promising alternatives to conventional materials for the development of next-generation, low-cost X-ray detectors with relevance in healthcare, security, and industrial applications.
In this work, composite active layers were fabricated by incorporating ZnO nanoparticles into a P3HT matrix at different doping ratios (1:0.25, 1:0.5, and 1:0.75). ZnO was selected owing to its high electron mobility, wide bandgap, and thermal stability. The nanoparticles were synthesized via the sol–gel method and integrated into P3HT, followed by the fabrication of resistive-type devices with interdigitated electrodes (IDT/P3HT:ZnO).
The effect of ZnO nanoparticle concentration on the device performance was systematically investigated. Increasing ZnO content was found to facilitate electron transport and significantly enhance the sensitivity to X-rays. The device with a 1:0.75 P3HT:ZnO ratio demonstrated the most favorable performance, exhibiting the highest sensitivity (0.79 μGy/s) along with a rapid response. Electrical characterization revealed pronounced variations in the current response under different X-ray doses, confirming the active contribution of ZnO nanoparticles to the detection mechanism. This study was supported by TÜBİTAK, project number: 123F131.Speaker: Sadullah Ozturk (Istanbul University-Cerrahpasa (TR))
-
78
-