Two current-based microscopic analysis methods - TSC and I-DLTS - with current injection and/or optical filling (in development) were recently and effectively used by CERN RD50 Acceptor Removal project group as reciprocal tools in the investigation of highly irradiated p-type silicon sensors and their related radiation hardness study aiming to understand and parametrise the existing acceptor...
Abstract: The radiation induced BiOi defect complex by 6 MeV electrons in low resistivity (10 Wcm) p-type epitaxial silicon diodes has been studied using the Thermally Stimulated Current (TSC) and the Thermally Stimulated Capacitance (TS-Cap) technique. The fluence values were in the range between 1 × 1015 e/cm2 and 6 × 1015 e/cm2. The extracted results on the activation energy, defect...
Our study focused on the BiOi defect, as determined from DLTS and TSC experiments, in connection with the acceptor removal rates in B-doped silicon PAD and LGAD diodes irradiated with 23 GeV protons and 1 MeV neutrons. We followed the dependencies on doping, irradiation fluence and particle type in a try of understanding the large scattering in the results reported previously for acceptor...
Three-dimensional Poole-Frenkel emission from BiOi was studied using three different approximations of the electric field inside the active p-type region. All three approaches for obtaining the TSC spectrum rely on the same assumption that every emitted charge is captured by the electrode without the possibility for recombination or re-trapping. With this common approximation the electric...
To investigate the acceptor removal by irradiation, high resistivity FZ silicon samples are implanted by boron, gallium and indium. A co-implantation with oxygen, carbon, nitrogen and fluor is done as well. After Implantation the samples are annealed in an RTP furnace. The sheet resistance and low temperature photoluminescence (LTPL) spectra are measured. Then the samples are irradiated by...
The boom of silicon in semiconductor technologies was closely tied to the ability to control its density of lattice defects. After being regarded as detrimental to the crystal quality in the first half of the 20th century, point defects have become an essential tool to tune the electrical properties of this semiconductor, leading to the development of a flourishing silicon industry. At the...
This project focuses on the investigation of radiation damage of epitaxial p-type silicon.
Various test structures consisting of Schottky diodes and pn-junctions of different size and flavors have been fabricated at different facilities, including RAL and Carleton University. The structures are fabricated on a 6-inch wafer of various doping (1e13, 1e14, 1e15, 1e16, and 1e17 B cm-3) and 50...
High Resolution Transmission Electron Microscopy (HRTEM) is a milestone in the imaging of structural defects. A LGAD sample irradiates at a fluence of 1e19 1MeV neutrons/cm2 has been investigated with a JEOL 2100 system, equipped with high resolution polar piece. Structural changes subsequent to a 30 min isochronous thermal treatment @150C, 200C, 250C, 200C and 350C respectively have been...
To explore the timing performance of the wide bandgap semiconductor devices, we measured the time resolution of 100 um 4H-SiC PIN device manufactured in China using the beta source and LGAD as reference. A simulation has been carried out to investigate the timing performance. We also reported the prospects of 4H-SiC with gain layer structure (LGAD) using the TCAD simulation.
SiC devices can work at high irradiation fluence and temperature environment, and 3D-SiC devices can achieve good time resolution and high charge collection, which makes it have broad application prospects. This report contains the time resolution simulation of 2D SiC devices and the comparison between measurement data and 2D simulation. The understanding of time resolution simulation of SiC...
The study is focused on the impact of heavily damaged Bragg peak region (BPR), which arises in Si p+-n-n+ diodes at the end of 15 um track of 53.4 MeV 40Ar ions on the degradation of the bulk current The method of the study included simulation of ion collisions with the silicon atoms, the measurements of I-V and C-V characteristics of irradiated diodes and their treatment using a specially...
The first 25 and 35 m$\mu$ thick LGAD sensors produced at FBK have been irradiated with neutrons up to 1$\cdot$10$^{17}$ n$_{eq}$/cm$^2$.
The preliminary electrical characterisation of the irradiated sensors will be presented.
The plans towards the next production of thin sensors optimised for extreme fluences will be discussed.
The vast majority of foreseen upgrades to existing particle physics detectors, as well as future Linear Collider experiments will continue to be based on silicon sensors as main tracking device. This means sensors will become even more of a cost driver than they already are today. In addition, sensors in the Float-Zone technology currently used in the LHC experiments are available from only a...
CMOS process lines are an attractive option for the fabrication of hybrid pixel sensors for large-scale detectors like the ATLAS and CMS detectors. Besides the cost-effectiveness and high throughput of commercial CMOS lines, multiple features like poly-silicon layers, metal-insulator-metal capacitors and several metal layers are available to enhance the sensor design.
After an extensive R&D...
The motivation of this study is the development of next generation capacitively coupled (AC-coupled) pixel sensors with coupling insulators having good dielectric strength and radiation hardness simultaneously. The AC-coupling insulator thin films were aluminum oxide (Al$_2$O$_3$) and hafnium oxide (HfO$_2$) grown by Atomic Layer Deposition (ALD) method. The Al$_2$O$_3$ thin films were...
Low Gain Avalanche Detectors (LGADs) is one of the most promising sensing technologies for future 4D-tracking applications and recently it has been qualified to be used in the ATLAS and CMS timing detectors for the HL-LCH upgrade. LGADs are able to achieve an excellent timing performance by the presence of an internal gain that improves the signal-to-noise ratio leading to a better time...
The study of a Low Gain Avalanche Detector (LGAD) has been carried out by Ion Beam Induced Charge (IBIC) and Time Resolved Ion Beam Induced Charge (TRIBIC) using the nuclear microbeam line of the Centro Nacional de Aceleradores (CNA). For that purpose, a 3 MeV H ion beam was employed, and the results were compared to that obtained by the Transition Current Technique (TCT) using an infrared...
Techniques for silicon detector characterization have predominantly relied on the laser methods such as TCT and quite recently TPA-TCT. We show that the Ion Beam Induced Charge (IBIC) technique has great potential in future LGAD characterizations. The LGAD sensors, 200 um thick and arranged in a 2x2 array configuration with a nominal interpad distance of 50 um were tested. The microprobe...
The Institute of High Energy Physics, Chinese Academy of Sciences (IHEP, CAS) has designed two types of LGAD sensors, which are produced in the Novel Device Laboratory (NDL) and Institute of Microelectronics (IME) respectively. The sensors of the two foundries were irradiated with neutrons to fluences of 0.8e15, 1.5e15 and 2.5e15 neq/cm2 in Institut Jozef Stefan (JSI). The timing resolution...
Effective interpad distance of non-irradiated and irradiated LGAD prototypes from HPK and FBK was measured and compared to simulations. The effective interpad distance is substantially larger than nominal before irradiations and becomes nominal after irradiations. The measurements were compared with simulations which showed that the field lines from a sizeable region at the edge of the pad end...
A High-Granularity Timing Detector (HGTD), based on low gain avalanche detector (LGAD) technology, is proposed for ATLAS Phase-II upgrade. The USTC Group is involved in this project and has been developing the LGAD sensor technology. In this talk, we will report the recent results of USTC-1.1 LGAD sensors, which are designed by USTC and fabricated at IME (Institute of Microelectronics ,CAS)....
A comprehensive review of the characterization results of neutron-irradiated (up to a fluence of $2.5 \times 10^{15} n_{eq}/cm^2$) LGADs manufactured at IMB-CNM in the context of the AIDA-2020 project will be given. The single-diode LGADs studied have an architecture that corresponds to that envisaged for the high-luminosity LHC MIP timing detectors.
In this contribution we will present the first measurements on neutron-irradiated LGADs corresponding to our 6-inch, 50µm active layer thick, epitaxial wafers run (6LG3). Samples were fabricated using three boron implantation doses, and one energy, for the gain layer definition. Gain, collected charge, acceptor removal constant and timing measurements were carried out on these LGADs irradiated...
The need for 4D (fast timing) silicon particle detectors has become very apparent with the introduction of the High-Luminosity upgrade at the LHC. Timings on the order of 10’s picoseconds will be required in order to fully reconstruct trajectories along the beam line where the intensity is largest and post-collision reconstruction with 3D detectors is insufficient.
The University of Oxford,...
In this work, we present the principle of operation of an innovative sensor for neutron detection obtained by depositing a thin layer of converter, about 35 microns of 6LiF, on a multi-pad AC-LGAD. When the neutrons are captured in the converter, the ensuing emission of alpha particles and/or tritium nucleuses is recorded by the silicon sensor. In this study, the AC-LGAD is first glued on a...
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...
We present measurements of AC-LGADs performed at Fermilab test beam facility. We also present first test beam results of sensors which utilize a buried gain layer. The buried layer is formed by patterned implantation of a 50-micron thick float zone substrate wafer-bonded to a low resistivity carrier, followed by epitaxial deposition of the amplification region. We studied strip and pixel...
Low Gain Avalanche Detectors (LGADs) are thin silicon detectors with moderate internal signal amplification. LGADs can provide time resolution of few 10’s of pico-seconds for minimum ionizing particles. In addition, the fast rise time and short full charge collection time (as low as 1 ns) of LGADs are suitable for high repetition rate measurements in photon science and other fields. However...
The development of next-generation silicon sensors is directed towards improving the spatial and temporal resolution of today’s particle trackers. To this end, our group in Turin recently developed a solution that features the combination of silicon LGAD (Low Gain Avalanche Detector) sensors with FAST, an integrated device responsible for both amplification and basic processing of the signal....
We present measurements on AC-LGADs (also named Resistive Silicon Detectors RSD), a version of LGAD which has shown to provide spatial resolution on the few 10‘s of micrometer scale based on charge sharing among neighboring pads.
Using focused IR-Laser scans directed alternatively at the read-out side on the front and the bias side on the back of the AC-LGAD, RSD produced by FBK have been...
Finely segmented 3D pixel sensors are being considered for the innermost layer of the Phase-2 Tracker upgrade of CMS due to their intrinsic radiation tolerance and low demanding power consumption. No significant degradation of performance is observed up to fluences of 1e16 neq/cm2.
The innermost layer of the Phase-2 Tracker will be placed as close as 3 cm from the beam and will extend 20...
We report on the measurements of time resolution for double-sided 3D pixel sensors with a single cell of 50 $\mu$m $\times$ 50 $\mu$m and thickness of 285 $\mu$m, fabricated at IMB-CNM and irradiated with reactor neutrons to different radiation doses up to 1e16 MeV n$_{eq}$/cm$^2$.
In my talk I will present the results of the first fabrication of
n-on-n 3D detectors. The sensors have been irradiated with neutrons at
fluences up to 1E17n/cm 1 M-ev/equivalent. Using the TCT set up
available at CNM we have been able to do the measurements before
irradiation both of the charge collection efficiency and the timing
performance using a 50x50 pixel array with a pitch of...
The Transient Current Technique (TCT) has become a very important tool for characterization of unirradiated and irradiated silicon detectors. In recent years a novel method, the Two Photon Absorption - Transient Current Technique (TPA-TCT), based on the charge carrier generation by absorption of two photons, was developed. TPA-TCT proved to be very useful in 3D characterization of silicon...
The Transient Current Technique (TCT) has become a very important tool for characterization of unirradiated and irradiated silicon detectors. In recent years a novel method, the Two Photon Absorption - Transient Current Technique (TPA-TCT), based on the charge carrier generation by absorption of two photons, was developed. TPA-TCT proved to be very useful in 3D characterization of silicon...
A new TPA-TCT system based on FYLA fs laser has been assembled at JSI. The setup and first measurements will be presented in this talk.
The Transient Current Technique (TCT) is used to investigate the
response of silicon diodes. Electron-hole pairs are generated close to
the surface by illuminating the diode with two sources: either a pulsed
red-light laser or $\alpha$-particles. These charge carriers drift in the electric
field and induce transient currents on the diodes electrodes. The charge
collection of a diode is...
The previously introduced technique of edge-on measurement using an electron beam for pad diodes has been studied further. The method has been
improved in several aspects: the spatial resolution (by a factor of 2), the precision of the in-situ alignment (by a factor of 2.5), and the statistical errors (by
a factor of 2.0).
In this study, the pad diodes have areas of 25 mm2 and 12.5 mm2
, a...
The HL-LHC presents unprecedented challenges and timing information is expected to play a key role in mitigating the impact of pile-up in both ATLAS (HGTD) and CMS (MTD-ETL). However, yield and stability after heavy irradiation remain a concern. The presented results are the results of the main part of the second big experimental campaign on LGAD fatalities and its irreversible breakdown after...
Aside from the SPA mortality studies, the first attempts with the TPA mechanism have been performed. In particular, the stability and mortality of the system were monitored with well localized TPA generation of charge in different depths of the device (Z – direction). The first results suggest that the stability of the devices varies rather weakly as long as the charge is generated inside the...
LGAD sensors will be employed in the CMS MTD and ATLAS HGTD upgrades to mitigate the high levels of pileup expected in the High Luminosity phase of the LHC. Over the last several years, much attention has focused on designing radiation tolerant gain implants to ensure these sensors survive the fluences expected, in excess of 1-2 x 10^15 neq/cm^2. As verified with beta source measurements, the...
The purpose of the proposed acquisition system is to provide a all-in-one solution that be able to capture and process the data generated for up to 4 Roc4Sens readout chips simultaneously. In order to achieve this goal, the system is composed of a FPGA Zynq Ultrascale+, a custom PCB and a management software. Thus, the operator will be able to manage the entire acquisition system from the GUI...
Monolithic CMOS active pixel sensors in depleted substrates (DMAPS) are an attractive development for pixel tracker systems in high-rate collider experiments. The radiation tolerance of these devices is enhanced through technology add-ons and careful design, which allow them to be biased with large voltages and collect charge through drift in highly resistive silicon bulks. In addition, the...
The high-luminosity upgrade of the LHC (HL-LHC) leads to new requirements on the detectors. With the availability of highly resistive silicon from commercial CMOS vendors, there are ongoing efforts to build depleted monolithic active pixel sensors (DMAPS) for high energy particle detectors. TJ-Monopix is a family of such a pixel sensor in 180 nm TowerJazz technology implementing a small...
RD50-MPW3 is a new prototype HV-CMOS ASIC, developed by the CERN-RD50 CMOS Working Group, whose submission for fabrication is planned for Q4 2021. It is the most advanced prototype of the RD50-MPWx series. RD50-MPW1 includes a fully monolithic matrix of 40 x 78 pixels, with a very small 50 µm x 50 µm pixel area that integrates both analog and FE-I3 style digital readout electronics inside the...
We would present a very recent experiment about the working of the MPW2 monolithic detector chip prototype under proton and ion microbeams at the RBI Pelletron facility. We plan to test the integrity of the memory cells using a proton beam for aiming to the target by looking the Particle X ray emission (PIXE) and then shooting ions in mili broadbeam (around 1 mm2), and microbeam (around 1 um2)...
The CERN-RD50 collaboration aims to develop and study High Voltage-CMOS (HV-CMOS) sensors for use in very high luminosity colliders. Measurements will be presented for the RD50-MPW2 chip, a prototype HV-CMOS pixel detector with an active matrix of 8 x 8 pixels. The active matrix is tested with injection pulses, a radioactive source and a proton beam. The talk will cover the FPGA based DAQ...
The RD50-CMOS group aims to design and study High Voltage CMOS (HV-CMOS) chips for use in a high radiation environment. Currently, measurements are performed on RD50-MPW2 chip, the second prototype developed by this group.
The active matrix of the prototype consists of 8x8 pixels with analog frontend. Details of the analog frontend and simulations have been already published earlier....
