The Non Ionizing Energy Loss (NIEL) concept compares and scales the damage impacted on semiconductor devices in different radiation fields. A particular weakness of the present NIEL concept consists in the inability to predict the different formation rates of cluster and point defects in the silicon (Si) crystal for different particles and particle energies. Specifically, differences between...
This project focuses on the investigation of trap energy levels introduced by radiation damage in epitaxial p-type silicon. Using 6-inch wafers of various boron doping concentrations (1e13, 1e14, 1e15, 1e16, and 1e17 cm-3) with a 50 µm epitaxial layer, multiple iterations of test structures consisting of Schottky and pn-junction diodes of different sizes and flavours are being fabricated at...
This project focuses on the investigation of radiation damage of epitaxial P-type silicon.
Various test structures consisting of Schottky diodes and p junctions of different sizes and flavors have been fabricated at different facilities, including RAL and Carleton University.
The structures are fabricated on 6 inch wafers of various doping (1e13, 1e14, 1e15, 1e16, and 1e17 B cm-3) and 50...
Experimental evidence for the explanation of light-induced degradation (LID) in silicon by the A_Si-Si_i-defect is summarized [1, 2]. Based on these findings, a possible involvement of the B_Si-Si_i-defect in the acceptor removal phenomenon of low-gain avalanche detectors (LGAD) [3] with a boron-doped gain layer is discussed. An outlook on density functional theory (DFT) based calculations of...
In this work, the macroscopic (I-V, C-V) and microscopic (Thermally Stimulated Current(TSC) and Capacitance(TS-Cap)) measurements were used to investigate the properties of high resistivity p-type diodes irradiated with 60Co gamma-rays with dose values of 10, 20, 100 and 200 Mrad. Two types of diodes are manufactured using p-stop and p-spray to isolate pad and guard ring, and both are FZ...
Silicon based sensors suffer from a phenomenon called “Acceptor removal” when exposed to high fluences of radiation. This “acceptor removal” process implies the elimination of the dopant element from the substitutional place (e.g., boron for p-type silicon) and combining with a different particle, obtaining an electrical active defect complex (in the case of boron-doped p-type silicon,...
The Horizon Europe project EURO-LABS will provide Transnational Access to Research Infrastructures (RI) for users from the Nuclear and Particle Physics communities. It comprises three pillars: Nuclear Physics, HEP Accelerators and HEP Detectors.
HEP Detectors RI's should be of vital interest to RD50. The RI's are grouped into 3 tasks dealing with Detector Characterization, Test Beams and...
The particle beam profilers, based on fluence measurements performed by recording the changes of carrier lifetime in Si material and scintillation intensity of thin GaN layers, caused by radiation induced defects and emission centres, will be presented. The beams of penetrative (26 GeV/c) and stopped (1.6 MeV) protons will be discussed.
Gallium nitride (GaN) and its related hetero-structure alloy AlGaN are wide band gap semiconductors which offer radiation-hard alternatives to silicon, particularly as the focus in the HEP community shifts toward technologies capable of operating in extremely high radiation fields such as fast hadron fluence greater than 1017 neq/cm2. High-electron mobility transistors (HEMTs) fabricated in...
In future nuclear fusion reactors, it will be essential to diagnose suprathermal ions escaping from the plasma. The escaping suprathermal ions imply a loss of energy that leads to plasma cooling, in addition to compromising the integrity of the reactor wall material [1]. For the future ITER (International Thermonuclear Experimental Reactor) project, it will be of crucial importance to detect...
A radiation tolerance study of planar diodes fabricated on a SiC substrate will be presented. TPA-TCT was used to characterize the samples. The measurement campaign was carried out at the laser facility of the EHU-UPV university.
Advanced fusion alpha-particle diagnostics in high D-T plasmas under high-fluences require efficient wide bandgap semiconductor detectors fabricated on 4H-SiC and Diamond materials. However, acquiring high-pure single crystalline diamond is difficult to fabricate large area detectors. This motivated to explore wide bandgap semiconductor 4H-SiC possessing high thermal conductivity suitable for...
Compared to Silicon (Si), silicon carbide (SiC) has multiple advantageous material properties, making it an interesting candidate for high beam rate detectors. SiC features a higher charge carrier saturation velocity and breakdown voltage than Si, which allows for a high time resolution and aids in mitigating pile-ups. The large band gap of SiC improves its radiation hardness, which, together...
Inspired by the Low Gain Avalanche Diode (LGAD) of Silicon, we investigate the possibilities to produce similar device using 4H-SiC, benefiting from the intrinsic characteristics of the wide band gap properties of Silicon Carbide, such as higher saturated carrier velocity, higher atom displacement energy as well as the recent technological improvement of high-quality epitaxy with high...
The irradiation effect of Schottky 4H-SiC detector has been studied at the Back-n white neutron beamline at China Spallation Neutron Source (CSNS). The total irradiation flux of the white neutron with an energy peak of 1 MeV, is about 1e14n/cm2.Before and after irradiation, the alpha particle energy spectrums are compared, and the influence of neutron irradiation on the polarization effect of...
A prototype of 360 um thick single crystal SiC has been fabricated with holes of 100um using laser drilling method. Form scanning electron microscope (SEM) images, there is no crack extending to the single crystal, and no residue on the side wall. It is found that the SiC sidewall is carbon-riched after laser and chemical treatment. The electrodes of 3D 4H-SiC device are formed by extruding...
The ATLAS upgrade for HL-LHC includes the installation of an entirely new all-silicon Inner Tracker (ITk). The part of the tracker further away from the IP is instrumented with silicon micro-strip sensors comprising 165m2 of active area in a nearly hermetic way. Multiple sensor shapes are utilized: square sensors in the barrel part and a stereo-annulus sensor design with curved edges to...
In this work, charge collection profiles of non-irradiated and irradiated $150 \; \mu \text{m}$ $p$-type pad diodes were measured using a $5.2 \; \text{GeV}$ electron beam traversing the diode parallel to the readout electrode. Four diodes were irradiated to $1 \; \text{MeV}$ neutron equivalent fluences of 2, 4, 8, and $12 \times 10^{16} \; \text{cm}^{-2}$ with $23 \; \text{MeV}$ protons. By...
In the following years, the LHC is going to be upgraded to the so called High Luminosity LHC (HL-LHC). Therefore, the CMS (Compact Muon Solenoid) detector will be adapted to the new conditions by incorporating new silicon sensors into the tracker and the calorimeter endcap. The strategy to monitor the quality and stability of the sensor production process is based on a test structure set,...
An effective approach for evaluating the scenario of Si sensor radiation degradation requires parametrization of the bulk current generation and the electric field transformation in the irradiated sensors. The presented data show that the I-V characteristics of Si sensors damaged by short-range particles allow a reliable differentiating between these processes and defining the parameters of...
Dear Colleagues,
Radiation sensors and detectors are widely used in fundamental physics, nuclear reactors, aerospace science, medicine, environmental monitoring, etc. One of the most important aspects of these application areas is the extremely harsh radiation environment, driven by the next-generation fusion energy reactors and future high-energy particle detectors. It is crucial to...
1 Vilnius University (LT)
2 Byelorussian State University (BY)
Corresponding author : algirdas.mekys@ff.vu.lt
Abstract: The radiation induced defects in silicon changes charge carrier transport properties, which are investigated by Hall and magnetoresistivity measurement techniques. The study concentrates on p-type Si material showing recent interest in BiOi defect formation. The...
To study the charge collection efficiency of radiation-damaged silicon
sensors, frequently red and near-infrared light is used to generate
electron-hole pairs . In order to determine the absolute number of
produced charge carriers, the light absorption coefficient, $\alpha$,
has to be known.
To study the change of $\alpha$ due to radiation-induced defects, we
have measured the...
Recently, semiconductive polymeric materials have attracted attention as an active layer for the detection of ionizing radiation because of their excellent properties such as flexibility, easy production, solution processability and low-cost production. This paper presents X-ray detection properties of Poly(3-hexylthiophene) (P3HT) : Phenyl C61 butyric acid methyl ester (PCBM) blend structure...
The implementation of resistive read-out in the design of silicon sensors places built-in charge sharing among neighboring pixels as the basic principle of operation. Resistive Silicon Detectors (RSD), exploiting the signals seen on the electrodes surrounding the impact point, achieve micron-level position resolution even with very large pixels. In this paper, results obtained with sensors...
In order to understand better the performance of LGADs, in particular in terms of Gain and breakdown voltage, it is important to know with high precision the structure of the devices and have a very accurate impact ionization model. There are several impact ionization models in the literature and many studies have been done in this respect, but no one is able to fit the empirical data taken in...
The radiation hardness of LGAD depends on the distribution and doping concentration of implanted Carbon and Boron. Based on Secondary Ion Mass Spectrometry profile of IHEP_IMEv2 LGAD devices, the impact of implantation dose and thermal load of Carbon to the radiation hardness of LGAD is discussed. A model based on the SIMS data is implemented to fit the accepter removal coefficient of LGADs...
Abstract: In this contribution we will present the first measurements on LGADs corresponding to our CNM’s second engineering run based on 6-inch, 50µm active layer thick, epitaxial wafers (6LG3 technology). Some of the wafers were carbon enriched using two different doses and one implantation energy. For the gain layer, samples were fabricated using different boron doses and diffusion times...
LGADs irradiated up to 6e15 n/cm2 with reactor neutrons were annealed at high temperatures between 300C and 450C. Annealing was for 30 minutes in steps of 50C. CV measurements were made after each annealing step and a significant increase of gain layer depletion voltage was observed. Charge collection and timing resolution were measured with electrons from Sr-90 showing beneficial effect of...
The Low-Gain Avalanche Detector (LGAD) with timing resolution better than 35(70) ps before (after) irradiation is the key technology that has been studied by many RD50 institutes and is going to be used in the ATLAS HGTD upgrade. The University of Science and Technology of China (USTC) has been developing LGAD sensors with the Institute of Microelectronics of the Chinese Academy of Sciences...
The High Granularity Timing Detector (HGTD) project of ATLAS will reduce the pile-up effect in HL-LHC by providing precise time measurement of tracks. The Low Gain Avalanche Detector (LGAD) with a time resolution better than 35(70) ps before(after) irradiation is the key technology that has been studied by many institutes. The Institute of High Energy Physics Chinese Academy of Science (IHEP)...
In this presentation I will overview our accumulated knowledge about limits of LGAD as studied using the low energy ions, low energy protons and femtosecond laser beams. A new insight into old data will be given as well. A proposal for a new experiment that will explore 30 MeV proton beams at the Cyclotron in Prague will be announced as well as the the future plans at RBI through Radiate user scheme.
In this presentation we will present the preliminary results from the interpad study in TI-LGADs using Femtosecond laser based SPA and TPA. The selected samples are from the latest FBK TI-LGAD production (RD50 project). To our best knowledge, the femtosecond laser based SPA and TPA has not been yet tested and tuned for the IP studies. .
The Two Photon Absorption – Transient Current Technique (TPA-TCT) setup at CERN uses fs pulse infrared fiber lasers, with a wavelength of 1550nm. Highly focusing optics are used to mainly generate excess charge carriers in a small volume (approximately 1µm × 1µm × 20µm) around the focal point of the laser beam, which enables a resolution in all three spatial directions. The setup was used to...
The recently observed saturation of the charge multiplication mechanism in LGAD devices has been studied and characterised with an infrared laser used to replicate the particle charge deposition ranging from 1 to 80 equivalent MIPs. The observations are compared to the response from beta particles and impinging protons with different energies. The influence of regions with high electric field...
In this contribution, the performances of several different guard-ring designs implemented in thin UFSD are compared. The sensors used in the analysis are part of the UFSD 4 production of the Fondazione Bruno Kessler.
The designs include different edge widths, numbers and layouts of floating guard-ring. The results include the measurement of noise and break-down voltage before and after irradiation.
Low Gain Avalanche Detectors (LGADs) are thin silicon detectors capable of providing measurements of minimum-ionizing particles with time resolution as good as 17 ps. These properties make LGADs the prime candidate technology for achieving 4D tracking in future experiments. Furthermore the fast rise time and short full charge collection time (as low as 1 ns) of LGADs are suitable for high...
Current and future collider experiments are reaching luminosities at which pile-up causes tracking of single particles to become near impossible when using only three spatial coordinates. However, with high enough timing resolution, an additional measurement coordinate could be introduced to unambiguously discern particle paths.
When it comes to ultra fast silicon detectors (UFSD), Low Gain...
The Large Hadron Collider (LHC) will be improved to be able to reach about seven times its current nominal instantaneous luminosity. The High-Luminosity LHC (HL-LHC), is planned to start operation in 2027. To face the consequent increase of the particle fluence close to the proton-proton interaction point, the ATLAS detector will include in its upgraded Inner Tracker (ITk) new sensor...
The proven potential of 3D pixel at higher than 10$^{16}$ n$_{eq}/cm^{2}$ radiation fluences, in combination with a small cell approach, makes them an ideal choice for a precision timing tracker. In this study, the timing resolution of several different geometry 3D pixel cells is presented using 160 GeV SPS pion beams. Through a varied incidence angle study, field uniformity, Landau...
We present a novel scalable graphene-silicon hybrid photodiode that enables deep UV imaging. We have a created a photodiode with a reduced dead layer entrance window. Existing photodiodes are limited in sensitivity for low wavelengths due to the low penetration depth of photons of < 400 nm. Typical photodiodes have a junction implant which causes the low penetrating photons to be recombined in...
The high energy physics group of PSI is involved in the CMS experiment. Since 2018 the group is also gaining experience in monolithic devices. This talk gives a summary of the group's DMAPS activities.
Highly integrated and very low power microelectronics, as required by Read Out Chips, represents a challenge because maximum performance and minimum power consumption are opposite design requirements. Quasi Floating Gate transistors are a solution because they allow independent control of transistor static and dynamic operation: AC and DC input terminals are different. The DC input terminal...
As a result of a CERN market survey, CMOS sensors in pixel and strip geometries were developed. The CMOS process is an established commercial industry process, which a lot of foundries utilize to produce silicon type devices. Typical CMOS foundries are equipped for bulk productions, but only for sensors much smaller than what is needed in e.g. the strip region of the ATLAS Inner Tracker. To...
The CERN-RD50 collaboration has been developing radiation hard High Voltage CMOS detector prototypes based on high resistivity substrate and large collection electrode, manufactured in LFoundry 150 nm process. In this contribution we will present measurements of timing properties of the RD50-MPW2 chip, which features an 8 x 8 matrix of active pixels with integrated analog front end and...
The CMOS Working Group of CERN-RD50 has designed and submitted RD50-MPW3, which is the third High Voltage CMOS (HV-CMOS) pixel chip developed by the collaboration to further study these sensors for future physics experiments. The design of RD50-MPW3 incorporates the lessons learnt from the previous two chips, RD50-MPW1 and RD50-MPW2. It inherits the structures for high breakdown voltage and...
This contribution can be seen as a continuation of the talk “RD50-MPW3: General details and pixel matrix”. This presentation focuses on the digital periphery of the chip and how it is integrated to the DAQ system, thus it is discussing a distinct topic.
A brief overview of the digital periphery is followed by a more detailed introduction of the data acquisition concept and software. The main...
Particle detectors systems need state of the art Data Acquisition Systems as backend. DRAD (Data Readout for Advanced Designs) is a a new DAQ with a client-server data architecture able to handle up to 4 Hybrid Pixel Detectors simultaneusly. At the present, DRAD operates with the OC4SENS read-out chip but is easily adaptable to other pixel detectors. The DAQ is based on a System-on-Module...
