33rd RD50 Workshop (CERN)

26 Nov 2018, 00:30 → 28 Nov 2018, 16:20 Europe/Zurich

6/2-024 - BE Auditorium Meyrin (CERN)

Michael Moll (CERN)

33rd RD50 Workshop on Radiation hard semiconductor devices for very high luminosity colliders

Monday, 26 November

LHC Full Detector Systems

Convener: Michael Moll (CERN)

1 Welcome to the 33rd RD50 Workshop and latest RD50 news

Speaker: Michael Moll (CERN)

181126-Welcome-Nov_2018-mm.pdf

181126-Welcome-Nov_2018-mm.pptx

2 Radiation Damage Monitoring and Modeling with Full Detector Systems at the LHC

This talk will be an overview of the inter-experiment (ATLAS, CMS, LHCb, ALICE) activities on monitoring and modeling radiation damage to our silicon detectors.

Speaker: Ben Nachman (Lawrence Berkeley National Lab. (US))

RD50TalkNovember2018.pdf

3 Discussion

Speakers: Ben Nachman (Lawrence Berkeley National Lab. (US)), Gregor Kramberger (Jozef Stefan Institute (SI)), Michael Moll (CERN)

181126-RD50_mm-5years - FullDetectorSystems.pdf

181126-RD50_mm-5years - FullDetectorSystems.pptx

10:30 Coffee break

Defects and Material Characterization

Convener: Michael Moll (CERN)

4 Development status of a novel proton irradiation site at the HISKP isochronous cyclotron Bonn

The development status of a novel proton irradiation site for silicon detectors is presented. The site is located at the isochronous cyclotron of the HISKP (Helmholtz Institut für Strahlen- und Kernphysik) of the University of Bonn. The cyclotron provides protons with up to 14 MeV kinetic energy with beam currents between a few nA and 1 $\mu$A. Light ions, such as deuterons, $^{3,4}$He or $^{12}$C, can also be produced with kinetic energies from 7 to 14 MeV per nucleon. The beam spot at extraction can be adjusted from a few mm to approximately 2 cm in diameter. An electron-cyclotron-resonance (ECR) source with low source-noise enables a stable beam over time. Dedicated secondary-electron monitors with custom readout electronics have been developed for on-line beam-current and position monitoring. The intrinsic resolution of the readout electronics allows to measure the secondary-electron current with a precision of 1\%. The goal is to measure the primary beam current with comparable precision in order to reduce the uncertainty on the proton fluence at the device. Preliminary beam-current calibrations are shown. GEANT4 simulations of energy distributions along the beam line up to the setup conclude a proton hardness factor of $\kappa\approx 3$, allowing to irradiate up to $10^{16}\frac{\text{n.e.q}}{\text{cm}^2}$ in 60 minutes. The intended irradiation parameters such as temperature, scanning and shielding are presented as well as plans for measurements of proton and deuteron hardness factors.

Speaker: Pascal Wolf (University of Bonn)

development_status_proton_irradiation_Bonn.pdf

5 Measurement of E_eff for Irradiated and Annealed Diodes

The leakage current of silicon sensors and diodes depends on temperature. To compare measurements of devices obtained at different temperatures, it is necessary to understand the dependence of the bulk current on the temperature.
Bulk current measurements are used to obtain $E_{\text{eff}}$ values for proton irradiated n$^+$-in-n diodes up to a fluence of $3 \times 10^{15} \, \frac{\text{n}_{\text{eq}}}{\text{cm}^2}$ during different stages of annealing for voltages up to $1000\,$V. A power limit is used to exclude measurements with significant self-heating. This is a test if the established methods and parameters of scaling are applicable after annealing.

Speaker: Felix Wizemann (Technische Universitaet Dortmund (DE))

Scaling_Wizemann.pdf

6 Measurements of NitroStrip detectors irradiated with protons and neutrons

Nitrogen enrich material showed an improvement of some defects after irradiation. NitroStrip is a RD50 project that aims to compare nitrogen enriched silicon wafers with FZ, DOFZ and MCz material. This presentation will show laser measurements and electrical characterization of NitroStrip samples irradiated at different fluences with protons and neutrons.

Speaker: Jan Cedric Honig (Albert Ludwigs Universitaet Freiburg (DE))

NIT_28_11_18RD50.pdf

7 Sequence Dependent Mixed Irradiations

This presentation shows CV characteristics and charge collection measurements on strip sensors and diodes after mixed irradiation with 23$\,$MeV protons and 1$\,$MeV neutrons. Samples of different material types were irradiated with neutrons after protons and vice versa with a total fluence of 6e14$\,$n$_{\text{eq}}$/cm$^2$. The depletion voltage is monitored with CV characteristics after the first and second irradiation step. Annealing studies with seed signal measurements are performed after the full irradiation.

Speaker: Jan-Ole Gosewisch (KIT - Karlsruhe Institute of Technology (DE))

Mixed_Irradiations_Gosewisch.pdf

8 Characterization of silicon n+-p-p+ detectors with Al2O3 passivating layers grown by Atomic Layer Deposition method

The study focuses on evaluating the characteristics of n+-p-p+ silicon detectors with Al2O3 isolation films processed by Atomic Layer Deposition (ALD) method with a goal of determining the value of the charge density in the alumina layer providing detector stable operation at high voltage. For this, distribution of potentials over the multiple n+ rings implemented in the detector as Voltage Termination Structure (VTS) was studied experimentally. Simulation of the potentials and electric field was applied as a tool to extract the charge density Qf in Al2O3 providing appropriate detector performance.
The results showed: a) applicability of the punch-through model to VTS operation in n-on-p Si detectors; b) impact of the Al2O3 charge on the maximum electric field initiating carrier avalanche multiplication. Simulations allowed to define Qf of -(4-7)×1011 cm-2 as a value critical for VTS operation in the detector under study.

Speaker: Dr Elena Verbitskaya (Ioffe Institute)

33 RD50 wksh_Verbitskaya.pdf

12:40 Lunch break

9 Electrically defects in unirradiated p-type silicon detectors fabricated by different vendors

TBA

Speaker: Cristina Besleaga Stan (National Institute of Materials Physics )

not irradiated_corr_2.pdf

not irradiated_corr_2.pptx

not irradiated_IoanaPintilie.pdf

10 Defect investigations in 1 MeV neutron irradiated PiN pads and LGADs

TBA

Speaker: Cristina Besleaga Stan (National Institute of Materials Physics)

irradiated_corr.pptx

irradiated_IoanaPintilie.pdf

11 Acceptor removal project in the framework of RD50 collaboration and last TSC results on p-type Si pad diodes

In present work a new common acceptor removal project in the framework of RD50 collaboration, role of each participant, type of measurement and samples distribution will be outlined.
The proton- and neutron-fluence dependent radiation damage effects, including change in leakage current, effective doping concentration, Neff, space charge sign inversion, but also introduction and annealing evolution of point- and cluster-defects have been studied in Si pad diodes fabricated from p-type EPI material of different resistivities (10-1000𝛀∙cm). Standard electrical characterisation and TSC (Thermally Stimulated Current) techniques were used.

Results of performed I-V, C-V and TSC measurements are discussed. A promising correlation between effective doping concentration Neff obtained from C-V measurements and defect concentration Nc extracted from TSC measurements for both neutron and proton irradiation is observed.

In TSC measurements a detailed analysis of the dominant peaks - E(30K), BiOi and three main deep acceptor levels H(116K), H(140K) and H(152K) - tentatively responsible for the change in the effective space charge is performed. The origin, field-enhanced and annealing behaviour of E(30) and H(40) and cluster-related defects are discussed as well.

Speaker: Yana Gurimskaya (CERN)

Copy of 33rd RD50 workshop_Gurimskaya_standard(3).pdf

Copy of 33rd RD50 workshop_Gurimskaya_standard(3).pptx

12 Status of TSC measurements at Hamburg - I. Nitrogen enriched versus standard FZ material, II. Acceptor removal after irradiation with 5.5 MeV electrons

Microscopic studies using the Thermally Stimulated Current (TSC) method have been performed on nitrogen enriched and standard n-type FZ samples. The devices were irradiated with 23 GeV protons at the CERN PS and with reactor neutrons at Ljubljana. For the trap filling during the TSC measurement cycles either a forward current of 1 mA was applied or light of 520 nm wave length was injected into the optical window at the p+-electrode. Further first annealing studies were undertaken at 60 °C up to 80 min. In addition I-V and C-V measurements have been compared with the microscopic results. The so far preliminary results indicate that an improvement of the radiation hardness by nitrogen enrichment as reported by P. Kaminski [1] could not be reproduced. More details about the comparison with standard FZ material will be presented.
In the second part first studies and results on TSC measurements on highly Boron doped EPI samples with a thickness of 50 µm and irradiated with 5.5 MeV electrons will be presented. One problem connected in TSC measurements with such highly doped material is the fact that the samples could not always be biased up to total depletion in order to extract exact concentration values. This will be discussed in the talk.
[1] P. Kaminski et al., 30-th RD50 Workshop, June 2017, AGH Krakow, Poland

Speaker: Eckhart Fretwurst (Hamburg University (DE))

TSC-NitroStrip and B removal.pdf

13 Comparative analysis of proton and ion damages in Si detectors supplemented with SRIM simulations

In the study impact of ⁴⁰Ar ion irradiation was compared with proton irradiation for scaling the silicon detectors degradation characteristics and evaluating the influence of the vacancy generation rate on the degradation. The ⁴⁰Ar ions with the total energy of 1.62 GeV were chosen since they provide uniform defect generation like 23 GeV protons. The values of the current related damage rate, introduction rates for microscopic defects and the effective space charge concentration were obtained from the experimental data at increasing ion fluence. The results are discussed using the data on vacancy generation obtained from SRIM simulation.

Speaker: Daria Mitina (Ioffe Institute)

Daria Mitina Report.pdf

14 Experimental Determination of Proton Hardness Factors at Various Irradiation Facilities.

The scheduled upgrade of the LHC to the HL-LHC presents new challenges in radiation damage studies. Around the world, campaigns to measure radiation hardness of detector sensors and components are being undertaken. Upon analysis of the I–V and C–V characteristics of BPW34F photodiodes, the hardness factors for proton beams at three different facilities have been measured. By computing the change in leakage current of the photodiodes pre- and post-irradiation as a function of proton fluence, the hardness factor of the University of Birmingham’s MC40 cyclotron was found to be 2.20 ± 0.08 for an energy of 25 MeV. For a beam energy of 23 MeV, and adopting a similar methodology, a value of 2.20 ± 0.28 was determined for the cyclotron at the Karlsruhe Institute of Technology. The hardness factor of the IRRAD proton facility at CERN was measured to be 0.62±0.02 for a beam energy of 24 GeV, which is consistent with an independent measurement of 0.63 with FZ sensors at IRRAD. The value for the MC40 cyclotron is in agreement with the currently quoted value, and the values for the IRRAD facility and the Karlsruhe Institute of technology agree with other independent studies.

Speaker: Cameron James Simpson-Allsop (University of Birmingham (GB))

slidesHardness (4).pdf

15:40 Coffee break

15 NIEL study of high energy heavy ions in silicon

Following the end of the 2017 and 2018 proton irradiation campaigns, high energy Xenon (2017) and Lead (2018) ions were delivered to the IRRAD facility at CERN. While the purpose of the heavy ion beams was mainly to test electronic components for Space in the CHARM facility downstream of IRRAD, dedicated experiments were also performed in which pad diodes were irradiated at different fluences in order to experimentally determine the hardness factor of the two new beams.

Speaker: Isidre Mateu (CERN)

33RD50_NIELinHeavyIons.pdf

33RD50_NIELinHeavyIons.pptx

16 Discussion

Speaker: Michael Moll (CERN)

181126-RD50_mm-5years - Defect-Material-Discussion.pdf

181126-RD50_mm-5years - Defect-Material-Discussion.pptx

Disscusion-_Defect_characterization-_33_RD50_workshop.docx

Disscusion-_Defect_characterization-_33_RD50_workshop.pdf

research plan_Defect_characterization..docx

research plan_Defect_characterization..pdf

Collaboration Board

Convener: Gregor Kramberger (Jozef Stefan Institute (SI))

Tuesday, 27 November

Precision Timing Detectors

Convener: Salvador Hidalgo Villena (Instituto de Microelectronica de Barcelona (IMB-CNM-CSIC))

17 Evolution of the working conditions and time resolution of UFSD sensors during the sensor lifetime at HL-LHC

In this presentation, we will review the evolution of the properties of UFSD sensors produced by different vendors as a function of fluence. We will show the expected working points and time resolution during the HL-LHC lifetime, and we will point out the differences among vendors.

Speaker: Nicolo Cartiglia (INFN Torino (IT))

Working_points.pdf

18 Performances of the third UFSD production at FBK

In this presentation we describe the third production of Ultra-Fast
Silicon Detectors (UFSD3) by Fondazione Bruno Kessler (FBK) in Trento,
in collaboration with University of Trento and National Institute of
Nuclear Physics (INFN) in Torino.
The new UFSD3 production has been designed in order to study specific
features requested for the future Endcap Timing Layer of CMS at the High
Luminosity LHC, such as uniformity and narrow interpad distance.
Uniformity studies have been done by FBK on wafer and in Torino on cut
structures.
Different strategies for gain termination implants have been pursued and
measurements of the resulting inactive space between pads have been
performed using the Transient Current Technique (TCT).
Plans towards future UFSD production at FBK will also be discussed.

Speaker: marta tornago

RD50_TornagoMarta.pdf

19 Development in Radiation hardness study on the third FBK production of Ultra fast silicon Detectors

A new Ultra Fast Silicon Detectors production (UFSD3) has been produced by Fondazione Bruno Kessler (FBK) in Trento, in collaboration with University of Trento and National Institute of Nuclear Physics in Turin (INFN).
This new UFSD batch has been produced on Silicon-on-Silicon Epitaxial and Float Zone wafers, with an active thickness of 50µm.
One of the target of the UFSD3 production is the improvement of the radiation hardness and the investigation of the initial acceptor removal mechanism in the multiplication layer (gain layer).
The previous Ultra Fast Silicon Detector production (UFSD2) demonstrated an improvement of the radiation hardness in UFSD sensors with Carbon co-implantation in gain layer; In UFSD3, 4 splits in Carbon dose have been used to investigate the acceptor removal mechanism.
We will report on electrical characterization of not-irradiated and irradiated devices, measurements of acceptor removal on sensors with four different Carbon doses co-implantation and preliminary comparison on irradiated UFSD3 and UFSD2 sensors.

Speaker: Marco Ferrero (Universita e INFN Torino (IT))

RD50_MarcoFerrero.pdf

10:30 Coffee break

20 Beam Test of Deep Diffused APDs

Deep diffused avalanche photodiodes are studied as timing detectors for minimum ionizing particles. This application does not require a radiator to generate light to be detected by the APD. The signal is generated and amplified within the APD bulk.
In this talk, preliminary results of a beam test characterization of deep diffused APDs are presented. The beam test setup comprised an MCP-PMT used as a time reference and a beam telescope. These elements allow to study the behavior of various parameters as a function of the impact position of the particles on the detector.

Speaker: Matteo Centis Vignali (CERN)

presBeamTestAPDs.pdf

21 Innovative TCT studies on the breakdown of UFSD3 sensors by FBK

The third production of Ultra-Fast Silicon Detectors (UFSD3) was recently completed by Fondazione Bruno Kessler (FBK) in Trento.
This new production features pads and strips arrays with 4 different strategies of the gain implant termination, ranging from an inactive area comparable to UFSD2 production to a configuration with a much narrower width. This choice allows studying the impact of the inactive region width on the sensor properties.
In my contribution, I will present the laboratory measurements performed in the Torino Silicon Lab (INFN – University of Torino), aimed at studying in detail the breakdown voltage of UFSD3 sensors and its dependence on the width of the inactive area.
In particular, I will focus on the results achieved using a state of the art CCD camera and employing the Transient Current Technique (TCT) in an innovative way, which gave us a new tool for mapping the sensors hot spots.
Finally, I will report on the observation of micro-discharges occurring both in irradiated and un-irradiated UFSD3 sensors.

Speaker: Federico SIviero

UFSD3 Breakdown Studies (F.Siviero).pdf

22 Thin LGADs characterization using Ion Beam Induced Charge (IBIC) and Time-resolved IBIC at the Centro Nacional de Aceleradores

In this talk we will present the first results obtained within our RD50 project concerning the study of thin (50 µm) Low Gain Avalanche Detectors with four sectors.
Using a nuclear microprobe, with a lateral resolution of a few micrometers, we have analyzed the CCE homogeneity of the sensor and the behavior of the peripheral regions under proton irradiation. We will show the gain curve measured with protons at 3, 4 and 18 MeV and with an alpha source, and the experimental data will be compared with TCT results. In addition, crosstalk effects between different sectors have been observed using the scan system of the microbeam line. Finally, the transient signal of the induced carriers has been recorded at several voltages.

Speaker: Dr Carmen JIMENEZ RAMOS (National Accelerator Center)

33rd_RD50_MCJR.pdf

33rd_RD50_MCJR.pptx

23 Annealing and Characterization of Irradiated Low Gain Avalanche Detectors

Irradiated Low Gain Avalanche Detectors (LGADs) are investigated using the
Transient Current Technique (TCT). The sensors are irradiated to a fluence of $10^{14}$ $\mathrm{n_{eq}}$/$\mathrm{cm}^2$. For different annealing times (at 60°C), the collected charge, the gain and the
electric field profile is measured.

Speaker: Moritz Oliver Wiehe (CERN / Albert Ludwigs Universitaet Freiburg (DE))

mwiehe_33RD50_2018.pdf

24 Timing performance of small cell 3D silicon detectors

A silicon 3D detector with a single cell of 50x50 um2 was produced and evaluated for timing applications. The measurements of time resolution were performed for 90Sr electrons with dedicated electronics used also for determing timing resolution of Low Gain Avalanche Detectors (LGADs). The measurements were compared to those in LGAD and also simulations. The studies showed that the
dominant contribution to the timing resolution comes from the time walk originating from different induced current shapes for hits over the cell area. This contribution decreases with high bias volates, low temperature and small cell size. The values reached are around 30 ps for ( 50x50 um2, 150 V, -20C) which is comparable to time walk due to Landau fluctuations in LGADs. It improves for inclined tracks and larger pads composed of multiple cells. A good agreement between measurements and simulations was obtained, thus validating the simulation results.

Speaker: Gregor Kramberger (Jozef Stefan Institute (SI))

GK-RD50-Timing3D.pdf

12:40 Lunch break

25 Discussion

Speakers: Giulio Pellegrini (Universidad de Valencia (ES)), Gregor Kramberger (Jozef Stefan Institute (SI))

Discussion_new_structures.pdf

Discussion_new_structures.pptx

Device Simulation

Convener: Joern Schwandt (Hamburg University (DE))

26 Charge collection test and TCAD simulation of OVERMOS, a CMOS 180nm MAPS detector

We will present results of charge collection of OVERMOS, a high resistivity TJ 180nm CMOS MAPS, obtained using 1064 nm calibrated laser source.
Result include charge collection over pixel region, sampled with 5 um resolution, and charge collection time. Test results are compared with 3D TCAD optical simulations, taking into account SiO2 and CoSi2 attenuation.

Speakers: Dr E. Giulio Villani (STFC Rutherford Appleton Laboratory), Enrico Giulio Villani (Science and Technology Facilities Council STFC (GB)), Enrico Giulio Villani (STFC - Science & Technology Facilities Council (GB)), Giullio villani (Rutherford Appleton Laboratory)

EGV_CERN_NOV18.pdf

EGV_CERN_NOV18.pptx

27 Status on TRAMOS (Trapping MOS) and DotPix (QuantumDot Pixel) ongoing developments

Abstract: The DotPix project is the result of several attempts to design a new kind of pixel for inner vertex detectors arrays with enhanced point-to-point resolution. As experiments include the DEPleted FET (DEPFET) based detector or monolithic pixels, it is now important to design a pixel based on a single device, which can reach a resolution below the micron with reduced thicknesses allowing track reconstruction and vertex determination with unprecedented accuracy. This is necessary for the future e+e- colliders (FCC,ILC).The proposed pixel structure, based on MOS technology will be described with its different possible implementations. It comprises a buried gate, which acts as a charge-collecting electrode with memory effect and controls the current of a micron-size n-channel MOS transistor. The device may be downscaled. The design of an architecture compatible with a process flow close to standard CMOS has required the massive use of device simulations. We have identified the bottlenecks and we will describe the way we can overcome them in a near future.
Short Bibliography:
Nicolas T. Fourches, IEEE Transactions On Electron Devices, Volume 64, Issue 4, (2017) 1619-1623. http://doi.org/10.1109/TED.2017.2670681
France

Speaker: Dr Nicolas Fourches (IRFU/DEDIP/DePhyS CEA Saclay)

RD50-5.pdf

RD50-5.pdf

RD50-5.pptx

28 Discussion

Speakers: Joern Schwandt (Hamburg University (DE)), Marco Bomben (LPNHE & Université Paris Diderot, Paris (FR)), Marco Bomben (U. di Trieste)

js_RD50_20181127.pdf

15:20 Coffee break

Characterization Techniques

Convener: Gregor Kramberger (Jozef Stefan Institute (SI))

29 Novel view on extraction of charge carrier transport parameters from classical TCT

The main experimental instrument for study of the field distribution in irradiated silicon detectors is a transient current technique (TCT). It is shown in this study that even in the case of significant contribution of carrier trapping to the shape of current response, the raw data of regular TCT (shape of current response in pad detector) allow to derive the electric field distribution with accuracy better than 5%. The new approach was applied for treatment of experimental double peak responses obtained for irradiated detectors and demonstrated specific of E(x) evolution with the bias voltage.

Speaker: Artem Shepelev (Ioffe Institute)

Shepelev_Ioffe.pdf

Shepelev_Ioffe.pdf

Shepelev_Ioffe.pptx

30 Characterization of semiconductor detectors using IBIC imaging method

The Ion Beam Induced Current (IBIC) technique available at the Accelerator laboratory of the Ruder Boskovic Institute is using scanning microbeam to study the properties of various semiconductor devices. The characteristics of the IBIC provide us with information of the response of the material and the coordinate of the beam impact point. The focused IBIC technique allows us to map 2D spatially resolved Charge Collection Efficiency (CCE) of different pad and pixelated detector structures with few micrometer resolution.
Semiconductor devices, made of Si and CdTe, were characterized with 2 MeV proton microprobe with different bias settings to create a detailed charge collection studies. In this work we present results of IBIC scans, study the impact of anode material selection, and analyse the performance of the detectors.

Speaker: Aneliya Karadzhinova-Ferrer (Rudjer Boskovic Institute (HR))

IBIC_imaging_method-RBI-Aneliya.pdf

31 Discussion

Speaker: Gregor Kramberger (Jozef Stefan Institute (SI))

Techniques.pdf

Techniques.pptx

Social Dinner

WorkshopDinner.pdf

Wednesday, 28 November

Pixel and Strip Detectors

Conveners: Joern Lange (Georg August Universitaet Goettingen (DE)), Thomas Bergauer (Austrian Academy of Sciences (AT))

32 DAQ-ROC4Sens

Where we will present to the RD50 community our new DAQ card project, now near its completion, capable of managing up to 4 ROC4Sens hybrid pixel detectors, ideal for testbeams, with only one DAQ Card and no external server (the data server is incorporated into the hybrid FPGA, with simple TCP/IP external access). The system is even able to make data processing on site.

Speakers: Dr Francisco Rogelio Palomo Pinto (ETSI-USe), Francisco Rogelio Palomo Pinto (Universidad de Sevilla (ES)), Francisco Rogelio Palomo Pinto (Universidad de Sevilla (ES))

28Nov2018_RD50_CERN_Rogelio.pdf

28Nov2018_RD50_CERN_Rogelio.pptx

33 Characterization before and after irradiation of RD53A planar pixel modules

Pixel modules built with thin n-in-p planar sensors, produced at MPG-HLL, interconnected to RD53A read-out chips, have been characterized
before and after irradiation. Different sensor design have been implemented, to optimize the performance in view of the application
of these type of devices in the trackers at HL-LHC.
The results in term of hit efficiency obtained in beam tests at CERN SPS will be presented, with modules irradiated up to a fluence of 5e15 neq/cm2.

Speaker: Anna Macchiolo (Max-Planck-Institut fur Physik (DE))

MPP_IRR_RD53A_MODULES_V4.pdf

34 Processing of pixel detectors on p-type MCz silicon using atomic layer deposition (ALD) grown aluminium oxide

We report on the fabrication of DC- and AC-coupled n+-in-p pixel detectors on magnetic Czochralski silicon substrates, using aluminium oxide (Al2O3) thin films grown by atomic layer deposition (ALD) as dielectric and field insulator. Al2O3 thin films exhibit high negative oxide charge, and thus do not require p-stop/p-spray insulation implants between pixels. In addition, they provide higher capacitance densities than SiO2, permitting more efficient capacitive coupling of pixels.
For bias resistors, sputtered titanium nitride (TiN) is used.
The mask layout includes AC-coupled detectors compatible with the CMS PSI46dig readout chip, DC-coupled detectors with 50x50 um pixels in a geometry to match the new RD53A readout chip, as well reference structures, such as diodes and MOS capacitors.
Results of characterization of diodes and MOS capacitors with CV, IV, and TCT measurements are presented, and the effect of gamma irradiation on these devices is discussed. Results show the expected high negative charge of the Al2O3 dielectric and acceptable leakage currents. In both new and older devices, we observe the compensation of acceptors in the p-type Si bulk upon gamma irradiation, to the point of apparent type-inversion in some cases. Pixel detectors await flip-chip bonding and characterization with the appropriate readout chips.

Speaker: Jennifer Ott (Helsinki Institute of Physics (FI))

JOtt_RD50_Nov18_3.pdf

10:30 Coffee break

35 Performance of LPNHE/FBK/INFN thin planar \textit{n-on-p} silicon pixels after HL-LHC radiation fluences

The tracking detector of ATLAS, one of the experiments at the Large Hadron Collider (LHC), will be upgraded in 2024-2026 to cope with the challenging environment conditions of the High Luminosity LHC (HL-LHC). The LPNHE, in collaboration with FBK and INFN, has produced 130~μm thick n−on−p silicon pixel sensors which can withstand the expected large particle fluences at HL- LHC, while delivering data at high rate with excellent hit efficiency. Such sensors were tested on beam before and after irradiation both at CERN-SPS and at DESY, and their performances are presented in this paper. Beam test data indicate that these detectors are suited for all the layers where planar sensors are foreseen in the future ATLAS tracker: hit-efficiency is greater than 97% for fluences Φ≲7e15 neq/cm2 and module power consumption is within the specified limits. Moreover, at a fluence Φ=1.3e16 neq/cm2, hit-efficiency is still as high as 88% and charge collection efficiency is about 30%.

Speaker: Marco Bomben (LPNHE & Université Paris Diderot, Paris (FR))

bomben_lpnhe_irradiated_pixels_181128.pdf

36 Test beam results of irradiated silicon sensor with modified ATLAS pixel implantations

Planar n$^+$-in-n silicon pixel sensors with modified n$^+$-implantations were designed in Dortmund to cause electrical field strength maxima to increase charge collection after irradiation and thus increase particle detection efficiency. Baseline for the pixel designs was the pixel layout of the IBL planar silicon pixel sensor with a $250\,\mu$m $\times$ $50\,\mu$m pitch.
The modified pixel designs and the standard IBL design are placed on one sensor which can be read out by an FE-I4 to test and compare the different pixel designs.
After irradiation with protons and neutrons respectively the performance of several sensors is tested in test beam measurements.
The relative performance of the pixel designs is different for sensors irradiated to the same fluence with neutrons in Sandia compared to sensors irradiated with neutrons in Ljubljana or with protons at CERN PS.
In this talk the current status of our investigation is presented to explain these significant differences which are visible in in-pixel efficiency maps.

Speaker: Mareike Weers (Technische Universitaet Dortmund (DE))

RD50_MareikeWeers.pdf

37 Test beam characterization of irradiated (1E16n_eq/cm2) 3D pixel sensors readout with the RD53A ROC

Pixelated 3D sensors with two different cell form factors( 50 um x 50 um, and 25 um x 100 um with one and two junctions)
were characterized at the SPS test beam. The samples were fabricated at FBK using a single side technology.
Sensors were readout with the RD53A ROC. Results on hit efficiency, cluster size and hit position residuals for fresh and
irradiated (1E16 n_eq/cm2) samples are presented. The response against bias voltage and temperature is also considered.

Speaker: Andrea Garcia Alonso (Universidad de Cantabria (ES))

RD50-CERN-2018-Andrea.pdf

38 3D silicon sensors for ATLAS ITk pixel detector

The HL-LHC upgrade will set strong requirements on the radiation hardness of the innermost layer of the new ITk pixel detector of ATLAS due to the large particle fluence.
At the same time the high particle multiplicity will require to reduce the hit occupancy, especially in the large pseudo-rapidity regions of the detector.
The sensor technology that has proven its compliance with the requisites for the innermost layer of ITk is 3D silicon sensors, which has been selected as baseline given its superior radiation hardness.
New 3D silicon sensors have been produced at CNM (Barcelona) with a Silicon On Insulator (SOI) single sided technology. They feature geometries with small pixel cells of 50x50μm2 or 25x100μm2 and active substrates of 150μm and 100μm of thickness.The sensors have been flip-chipped and assembled at iFAE to the novel RD53A ASIC prototypes designed for HL-LHC. The full modules have been irradiated with protons to fluences foreseen for the innermost layer of ITk.
A characterisation before and after irradiation has then been performed in beam tests at CERN SPS with 120 GeV pions. Results will be reported in this contribution.

Speaker: Giulia Giannini (IFAE Barcelona)

Giannini_Giulia_RD50.pdf

12:20 Lunch break

39 Discussion

Speaker: Gianluigi Casse (University of Liverpool (GB))

Locandina Tredi 2019 A3.pdf

CMOS

Convener: Gianluigi Casse (University of Liverpool (GB))

40 Overview of design and evaluation of depleted CMOS sensors within RD50

This contribution describes the status of the design and evaluation of depleted CMOS sensors within the CERN-RD50 collaboration. In particular, we will present laboratory measurements of RD50-MPW1 and TCAD simulated results of the structures on this chip. The results obtained so far, especially those related to the leakage current generated by the sensors, necessitate the submission of a second test MPW prior to the fabrication of the planned large area submission (RD50-ENGRUN1). The second test MPW (RD50-MPW2) will integrate several passive single pixels with different features and one or two very small matrices of pixels with fast low-noise readout circuitry. The aim of RD50-MPW2 is to understand the origin of the leakage current generated by the sensors and to evaluate different approaches to minimizing this problem. We will report on the microelectronic design and TCAD simulations towards RD50-MPW2. We will also report on the progress of design work towards RD50-ENGRUN1. In particular, that related to the improvement of the time resolution of depleted CMOS sensors with the utilization of sampling circuitry.

Speaker: Eva Vilella Figueras (University of Liverpool (GB))

2018_Vilella_CERN_RD50_WS.pdf

41 Irradiation study of CMOS pixel detector structures on RD50-MPW1 chips from LFoundry

RD50 submitted a pixel detector prototype ASIC in the 150 nm CMOS technology at LFoundry. It contains two matrices of MAPS pixels and few test structures. The test structures include passive pixel arrays near the edge of the chip suitable for E-TCT measurements. The chips were manufactured on p-type silicon with two different initial resistivities around 500 Ohm-cm and 2000 Ohm-cm. Chips were irradiated with neutrons in Ljubljana up to maximal fluence of 2e15 n/cm2. Edge-TCT measurements were made with passive devices and evolution of effective space charge concentration on neutron fluence was measured for the two different initial resistivities. Results of this study will be presented in this contribution.

Speaker: Igor Mandic (Jozef Stefan Institute (SI))

RD50_nov_2018_Mandic.pdf

42 Options and constraints for passive sensor fabrication at CMOS foundries

With larger and larger areas to be covered for all-silicon trackers and even silicon-based calorimeters, production cost per sensor area and also production turnaround and throughput are becoming important aspects. CMOS foundries have a very large throughput on 8" wafers and may offer very competitive prices, but in turn impose several constraints. The presentation will summarise the pros and cons of CMOS foundries for planar sensor production.

Speaker: Daniel Muenstermann (Lancaster University (GB))

Muenstermann_passive_CMOS_sensors.pdf

43 Discussion

Speaker: Eva Vilella Figueras (University of Liverpool (GB))