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We introduce a double-sided variant of low gain avalanche detector, suitable for pixel arrays without dead-area in between the different read-out elements. TCAD simulations were used to validate the device concept and predict its performance. Different design options and selected simulation results are presented, along with the proposed fabrication process. [ABSTRACT FROM AUTHOR]

This paper deals with a radiation hardness study performed on double-sided 3D strip sensors with passing-through columns. Selected results from the characterization of the irradiated sensors with a beta source and a laser setup are reported and compared to pre-irradiation results and to TCAD simulations. The sensor performance in terms of signal efficiency is found to be in good agreement with that of other 3D sensors irradiated at the same fluences and tested under similar experimental conditions. [ABSTRACT FROM AUTHOR]

Abstract: In this work, we report on the noise and signal properties of n-on-p, 3D Double-Side Double Type Column (3D-DDTC) detectors fabricated at FBK-irst (Trento, Italy). Compared to full 3D detectors, devices made with this approach allow for a simpler fabrication process, but the efficiency and speed of the charge collection process critically depend on the column overlap and should be carefully evaluated. Measurements were performed on detectors in the microstrip configuration coupled to the ATLAS ABCD3T binary read-out. Spatially resolved signal efficiency tests made with a pulsed infrared laser setup and charge collection efficiency tests made with a β source setup are here reported. [ABSTRACT FROM AUTHOR]

Abstract: The projected luminosity upgrade of the large hadron collider (LHC), the sLHC, will constitute a challenging radiation environment for tracking detectors. Massive improvements in radiation hardness are required with respect to the LHC. In the layout for the new ATLAS tracker, silicon strip detectors (SSDs) with short strips cover the region from 28 to 60cm distance to the beam. These SSDs will be exposed to fluences up to , hence radiation resistance is the major concern. It is advantageous to fuse the superior radiation hardness of the 3D design originally conceived for pixel-style applications with the benefits of the well-known planar technology for strip detectors. This is achieved by ganging rows of 3D columns together to form strips. Several prototype sLHC detector modules using 3D SSD with short strips, processed on p-type silicon, and LHC-speed front-end electronics from the present ATLAS semi-conductor tracker (SCT) were built. The modules were tested before and after irradiation to fluences of . The tests were performed with three systems: a highly focused IR-laser with spot size to make position-resolved scans of the charge collection efficiency (CCE), a -source set-up to measure the signal levels for a minimum ionizing particles (MIPs), and a beam test with 180GeV pions at CERN. This article gives a brief overview of the performance of these 3D modules, and draws conclusions about options for using 3D strip sensors as tracking detectors at the sLHC. [Copyright &y& Elsevier]

Abstract: We report on the most recent results from an R&D activity aimed at the development of silicon radiation detectors with embedded front-end electronics. The key features of the fabrication technology and the available active devices are described. Selected results from the characterization of transistors and test structures are presented and discussed, and the considered application fields are addressed. [Copyright &y& Elsevier]

Abstract: In this work, we report on the design, fabrication, electrical and optical characterization of innovative silicon npn bipolar junction phototransistors, with a finger-shaped emitter implant. Different finger width and interfinger distances, emitter geometries, metal contacts and doping profiles have been implemented to study the impact on the current gain and the spectral responsivity. Such a finger emitter/base junction proved to significantly enhance both the current gain and the responsivity in the blue spectral region with respect to the standard fully implanted detector (maximum current gain of 158 and 72, and responsivity=0.25 and 0.20A/W, respectively). BJTs featuring an additional N-channel implant below the emitter n+-fingers were also successively fabricated and exhibit an improved current gain of 650. The comparison of experimental results for all the implemented geometries allow the identification of the best performing BJT, in terms of current gain and responsivity, and of a figure of merit which takes into account the two fundamental layout parameters affecting the optical and electrical performance: number of emitter fingers and their total perimeter. The new finger-BJTs will be employed as gas sensors after being coated with a metalloporphyrin sensing film, that changes its light absorption properties in the blue when interacting with the gas molecules. A functional measurement campaign has been scheduled with ethanol vapors at different concentrations. [Copyright &y& Elsevier]

Abstract: We report on JFET devices fabricated on high-resistivity silicon with a radiation detector technology. The problems affecting previous versions of these devices have been thoroughly investigated and solved by developing an improved fabrication process, which allows for a sizeable enhancement in the JFET performance. In this paper, the main features of the fabrication technology are presented and selected results from the electrical and noise characterization of transistors are discussed. [Copyright &y& Elsevier]

Abstract: We report on a PIN photodetector integrated with a Junction Field Effect Transistor (JFET) on a high-resistivity silicon substrate. Owing to a modified fabrication technology, the electrical and noise characteristics of the JFET transistor have been enhanced with respect to the previous versions of the device, allowing the performance to be significantly improved. In this paper, the main design and technological aspects relevant to the proposed structure are addressed and experimental results from the electrical characterization are discussed. [Copyright &y& Elsevier]

Focuses on a specially tailored fabrication technology aimed at the fabrication of silicon microstrip detectors with integrated front-end electronics. Uses of the technology; Characteristics of the fabrication process; Benefits from integrating radiation detectors; Suitability of a monolithic approach.

Proposes a compact, analytical model for the ohmic-side interstrip resistance of double-sided silicon microstrip detectors. Model concept, model equations and model parameters; Validation of the model concept and model outcomes; Implications for metal-oxide-silicon field-effect transistors.

Fully Depleted Monolithic Active Pixel Sensors (FD-MAPS) represent an appealing alternative to hybrid detectors for radiation imaging applications. We have recently demonstrated the feasibility of FD-MAPS based on a commercial 110 nm CMOS technology, adapted using high-resistivity substrates and backside post-processing. A p/n junction diode, fabricated on the detector backside using low-temperature processing steps after the completion of the front-side Back End of Line (BEOL), is reverse-biased to achieve the full depletion of the substrate and thus fast charge collection by drift. Test diodes including termination structures with different numbers of floating guard rings and different pitches were fabricated together with other Process Control Monitor structures. In this paper, we present the design of the backside diodes, together with results from the electrical characterization of the test devices, aiming to improve understanding of the strengths and limitations of the proposed approach. Characterization results obtained on several wafers demonstrate the effectiveness of the termination rings in increasing the breakdown voltage of the backside diodes and in coping with the variability of the passivation layer characteristics. A breakdown voltage exceeding 400 V in the worst case was demonstrated in devices with 30 guard rings with 6 μm pitch, thus enabling the full depletion of high-resistivity substrates with a thickness larger than or equal to 300 μm. Additionally, we show the first direct comparison for this technology of measured pixel characteristics with 3D TCAD simulations, proving a good agreement in the extracted operating voltages. [ABSTRACT FROM AUTHOR]

Abstract: Silicon strip detectors are widely used as part of the inner tracking layers in particle physics experiments. For applications at the luminosity upgrade of the Large Hadron Collider (LHC), the sLHC, silicon detectors with extreme radiation hardness are required. The 3D detector design, where electrodes are processed from underneath the strips into the silicon bulk material, provides a way to enhance the radiation tolerance of standard planar silicon strip detectors. Detectors with several innovative 3D designs that constitute a simpler and more cost-effective processing than the 3D design initially proposed were connected to read-out electronics from LHC experiments and subsequently tested. Results on the amount of charge collected, the noise and the uniformity of charge collection are given. [ABSTRACT FROM AUTHOR]

Abstract: We have largely improved the performance of our detector-compatible Si JFETs by optimizing the fabrication technology. New devices feature thermal noise values close to the theoretical ones, and remarkably low 1/f noise figures. In view of adopting these JFETs for X-ray imaging and HEP applications, bulk and surface radiation damage tests have been carried out by irradiating single transistors and test structures with neutrons and X-rays. Selected results from static and noise characterization of irradiated devices are discussed in this paper, and the impact of radiation effects on the performance of JFET-based circuits is addressed. [Copyright &y& Elsevier]

The sixth edition of the International Conference on “Advancements in Nuclear Instrumentation Measurement Methods and their Applications” (ANIMMA) was held in Portorož, Slovenia, from June 17–21, 2019. The conference attracted almost 300 participants from 32 different countries, coming from academy, research institutes, and industry to discuss new scientific and technical prospects in all fields where nuclear instrumentation and measurements techniques play a major role. The scientific program included 25 invited talks, 125 oral presentations, and 77 poster presentations on the following topics: fundamental physics; fusion diagnostics and technology; nuclear power reactors monitoring and control; research reactors; nuclear fuel cycle; decommissioning, dismantling, and remote handling; safeguards and homeland security; severe accident monitoring; environmental and medical sciences; and education, training, and outreach. [ABSTRACT FROM AUTHOR]

Small-pitch 3D pixel sensors have been developed to equip the innermost layers of the ATLAS and CMS tracker upgrades at the High Luminosity LHC. They feature 50 × 50 and 25 × 100 μ m 2 geometries and are fabricated on p-type Si–Si Direct Wafer Bonded substrates of 150 μ m active thickness with a single-sided process. Due to the short inter-electrode distance, charge trapping effects are strongly mitigated, making these sensors extremely radiation hard. Results from beam test measurements of 3D pixel modules irradiated at large fluences ( 10 16 n e q / cm 2 ) indeed demonstrated high efficiency at maximum bias voltages of the order of 150 V. However, the downscaled sensor structure also lends itself to high electric fields as the bias voltage is increased, meaning that premature electrical breakdown due to impact ionization is a concern. In this study, TCAD simulations incorporating advanced surface and bulk damage models are used to investigate the leakage current and breakdown behavior of these sensors. Simulations are compared with measured characteristics of 3D diodes irradiated with neutrons at fluences up to 1.5 × 10 16 n e q / cm 2 . The dependence of the breakdown voltage on geometrical parameters (e.g., the n + column radius and the gap between the n + column tip and the highly doped p + + handle wafer) is also discussed for optimization purposes. [ABSTRACT FROM AUTHOR]

Abstract: We report on the development of n-on-p, 3D Double-Side Double Type Column (3D-DDTC) pixel detectors fabricated at FBK-irst (Trento, Italy) and oriented to the ATLAS upgrade. The considered fabrication technology is simpler than that required for full 3D detectors with active edge, but the detector efficiency and radiation hardness critically depend on the columnar electrode overlap and should be carefully evaluated. The first assemblies of these sensors (featuring 2, 3, or 4 columns per pixel) with the ATLAS FEI3 read-out chip have been tested in laboratory. Selected results from the electrical and functional characterization with radioactive sources are discussed here. [Copyright &y& Elsevier]

The Source Follower (SF) as the first amplification stage of the front-end electronics has proven to be an effective tool for low-noise read-out of silicon radiation sensors. Since the noise properties of a well-designed amplification circuit are mainly determined by its very first stage, constraints on the subsequent electronics are relaxed. Moreover, since the SF is characterized by a low output resistance, once it is completely integrated into the detector substrate, the connections to the out-of-chip part of the circuit are also relaxed. The effectiveness of this solution and the overall performance of the system depend on the sensor properties. In this paper, by presenting analytical calculations and measurements, we identify the sensor types that could profit from the advantages provided by the integrated SF, and the devices where the SF shows some pitfalls. Although the results presented in this paper have been obtained with an integrated JFET technology, the conclusions are valid for whatever technology the SF is made. [ABSTRACT FROM AUTHOR]

Abstract: Vertex detectors for the next LHC experiments upgrades will need to have low mass while at the same time be radiation hard and with sufficient granularity to fulfil the physics challenges of the next decade. Based on the gained experience with 3D silicon sensors for the ATLAS IBL project and the on-going developments on light materials, interconnectivity and cooling, this paper will discuss possible solutions to these requirements. [Copyright &y& Elsevier]

Abstract: 3D silicon sensors, where electrodes penetrate the silicon substrate fully or partially, have successfully been fabricated in different processing facilities in Europe and USA. The key to 3D fabrication is the use of plasma micro-machining to etch narrow deep vertical openings allowing dopants to be diffused in and form electrodes of pin junctions. Similar openings can be used at the sensor''s edge to reduce the perimeter''s dead volume to as low as ∼4μm. Since 2009 four industrial partners of the 3D ATLAS R&D Collaboration started a joint effort aimed at one common design and compatible processing strategy for the production of 3D sensors for the LHC Upgrade and in particular for the ATLAS pixel Insertable B-Layer (IBL). In this project, aimed for installation in 2013, a new layer will be inserted as close as 3.4cm from the proton beams inside the existing pixel layers of the ATLAS experiment. The detector proximity to the interaction point will therefore require new radiation hard technologies for both sensors and front end electronics. The latter, called FE-I4, is processed at IBM and is the biggest front end of this kind ever designed with a surface of ∼4cm2. The performance of 3D devices from several wafers was evaluated before and after bump-bonding. Key design aspects, device fabrication plans and quality assurance tests during the 3D sensors prototyping phase are discussed in this paper. [Copyright &y& Elsevier]

Abstract: We present a new 3D detector architecture aimed at simplifying the manufacturing process making it more suitable for high volume production. In particular, the proposed device features electrodes of one doping type only, e.g., columns in a p-type substrate. We report on TCAD simulation results providing deep insight into the static and dynamic behavior of this detector, highlighting its advantages and potential drawbacks. The fabrication process we intend to use is also described along with results from the morphological characterization of the most critical technological steps. [Copyright &y& Elsevier]

Thin substrates are one of the possible choices to provide radiation hard detectors for future high-energy physics experiments. Among the advantages of thin detectors are the low full depletion voltage, even after high particle fluences, the improvement of the tracking precision and momentum resolution and the reduced material budget.In the framework of the CERN RD50 Collaboration, we have developed p–n diode detectors on membranes obtained by locally thinning the silicon substrate by means of tetra-methyl ammonium hydroxide etching from the wafer backside. Diodes of different shapes and sizes have been fabricated on 57 and 99 μm thick membranes. They have been tested, showing a very low leakage current (<0.4 nA/cm2) and, as expected, a very low depletion voltage (<1 V for the 57 μm membrane). The paper describes the technological approach used for devices fabrication and reports selected results from the electrical characterization. [Copyright &y& Elsevier]

The paper presents the simulation studies of 10 μ m pitch microstrips on a fully depleted monolithic active CMOS technology and describes their potential to provide a new and cost-effective solution for particle tracking and timing applications. The Fully Depleted Monolithic Active Microstrip Sensors (FD-MAMS) described in this work, which are developed within the framework of the ARCADIA project, are compliant with commercial CMOS fabrication processes. A set of Technology Computer-Aided Design (TCAD) parametric simulations was performed in the perspective of an upcoming engineering production run with the aim of designing FD-MAMS, studying their electrical characteristics, and optimizing the sensor layout for enhanced performance in terms of low capacitance, fast charge collection, and low-power operation. A fine pitch of 10 μ m was chosen to provide high spatial resolution. This small pitch still allows readout electronics to be monolithically integrated in the inter-strip regions, enabling the segmentation of long strips and the implementation of distributed readout architectures. The effects of surface radiation damage expected for total ionizing doses of the order of 10 to 10 5 krad were also modeled in the simulations. The results of the simulations exhibit promising performance in terms of timing and low power consumption and motivate R&D efforts to further develop FD-MAMS; the results will be experimentally verified through measurements on the test structures that will be available from mid-2021. [ABSTRACT FROM AUTHOR]

The growing interest toward the development of high‐Z–sensitized organic scintillators is related with the potential possibility to merge the advantages of organic materials with those of inorganics. In fact, organic plastic scintillators offer large‐area applications and fast response at a low cost, yet their performances for high‐energy photons and charged particles are limited by the poor stopping power related with low‐Z materials. The real‐time optical investigation in terms of steady‐state luminescence spectra of polysiloxane/quantum dot (QD) nanocomposite samples under 2 MeV proton irradiation is presented. Results show an increase in the light yield of the polysiloxane samples embedding QDs up to 8% in comparison with the undoped polymer, paving the way for high‐Z sensitization through QDs in polysiloxane‐based active radiation detection systems. [ABSTRACT FROM AUTHOR]

Recent advances in segmented low‐gain avalanche detectors (LGADs) make them promising for the position‐sensitive detection of low‐energy X‐ray photons thanks to their internal gain. LGAD microstrip sensors fabricated by Fondazione Bruno Kessler have been investigated using X‐rays with both charge‐integrating and single‐photon‐counting readout chips developed at the Paul Scherrer Institut. In this work it is shown that the charge multiplication occurring in the sensor allows the detection of X‐rays with improved signal‐to‐noise ratio in comparison with standard silicon sensors. The application in the tender X‐ray energy range is demonstrated by the detection of the sulfur Kα and Kβ lines (2.3 and 2.46 keV) in an energy‐dispersive fluorescence spectrometer at the Swiss Light Source. Although further improvements in the segmentation and in the quantum efficiency at low energy are still necessary, this work paves the way for the development of single‐photon‐counting detectors in the soft X‐ray energy range. [ABSTRACT FROM AUTHOR]

Abstract The INFN CSN5 "TIMESPOT" project aims at the development and implementation of a complete integrated tracking system featuring very high precision both in space and in time for every pixel. Within this framework we are developing 3D pixel sensors optimized for timing, while retaining their usual advantages of low depletion voltage, extreme radiation hardness, and active edges. The pixel geometries are being optimized in terms of size, electrode configuration and shape. In particular, trenched electrodes are used instead of columns, so as to achieve more uniform electric and weighting field profiles. No established technology exists for 3D sensors with trenched electrodes, so we have developed and tested the necessary process steps. In this paper we report the main design and fabrication issues and selected results from TCAD simulations. Highlights • We report on 3D pixel sensors with trenched electrodes optimized for timing. • We thoroughly discussed the design and technological aspects. • We studied with TCAD the trade-off between intrinsic speed and pixel capacitance. • We demonstrated the technological feasibility of the proposed geometries. [ABSTRACT FROM AUTHOR]

Position-resolved timing characterisation tests were performed on individual pixels of hexagonal and trench 3D silicon sensors. An IR laser was used to deposit energy equivalent to 1 MIP with a 1 μ m spatial resolution onto each sensor, which were attached to custom-designed fast read-out electronics chips. Time of Arrival (ToA) values obtained were (544 ± 29.8) ps for the hexagonal geometry, and (515 ± 8.2) ps for the trench geometry. • IR laser scan performed on single pixels of hexagonal and trench 3D silicon sensors. • 1 MIP of energy was deposited, using a 1-micron space resolution in the scan. • Timing resolution of hexagonal pixel was 29.8 ps. • Timing resolution of trench pixel was 8.2 ps. [ABSTRACT FROM AUTHOR]

Cross-talk characterization results of high-fill-factor single-photon avalanche diode (SPAD) arrays in CMOS 150-nm technology are reported and discussed. Three different SPAD structures were designed with two different sizes (15.6 and 25.6  μm pitch) and three guard ring widths (0.6, 1.1, and 1.6  μm). Each SPAD was implemented in an array, composed of 25 (5×5) devices, which can be separately activated. Measurement results show that the average cross-talk probability is well below 1% for the shallow-junction SPAD structure with 15.6  μm pitch and 39.9% fill factor, and 1.45% for the structure with 25.6  μm pitch and 60.6% fill factor. An increase of cross-talk probability with the excess bias voltage is observed. [ABSTRACT FROM AUTHOR]

In this paper, a CMOS image sensor based on avalanche photodiodes (APDs) for time-of-flight optical ranging is presented. In-pixel phase-sensitive detection was obtained thanks to the modulation of APD avalanche gain. A pixel based on this principle with 30- \mu \textm pixel pitch and 25.7% fill factor was designed, and a $64 \times 64$ APD image sensor was fabricated in a 0.35- \mu \textm standard CMOS process. The maximum demodulation contrast measured on the array exceeds 85% at 25-MHz modulation frequency. High-frequency modulation was demonstrated on single test pixels, where a demodulation contrast as high as 80% was measured at 200-MHz modulation frequency. A 3-D camera working at a frame rate up to 200 frames/s was realized and characterized. [ABSTRACT FROM AUTHOR]

Abstract: The CMS silicon pixel detector is the tracking device closest to the LHC p–p collisions, which precisely reconstructs the charged particle trajectories. The planar technology used in the current innermost layer of the pixel detector will reach the design limit for radiation hardness at the end of Phase I upgrade and will need to be replaced before the Phase II upgrade in 2020. Due to its unprecedented performance in harsh radiation environments, 3D silicon technology is under consideration as a possible replacement of planar technology for the High Luminosity-LHC or HL-LHC. 3D silicon detectors are fabricated by the Deep Reactive-Ion-Etching (DRIE) technique which allows p- and n-type electrodes to be processed through the silicon substrate as opposed to being implanted through the silicon surface. The 3D CMS pixel devices presented in this paper were processed at FBK. They were bump bonded to the current CMS pixel readout chip, tested in the laboratory, and testbeams carried out at FNAL with the proton beam of 120GeV/c. In this paper we present the laboratory and beam test results for the irradiated 3D CMS pixel devices. [Copyright &y& Elsevier]

We report on the main design and technological characteristics related to the latest 3D sensor process developments at Fondazione Bruno Kessler (FBK, Trento, Italy). With respect to the previous version of this technology, which involved columnar electrodes of both doping types etched from both wafer sides and stopping at a short distance from the opposite surface, passing-through columns are now available. This feature ensures better performance, but also a higher reproducibility, which is of concern in medium volume productions. In particular, this R&D project was aimed at establishing a suitable technology for the production of 3D pixel sensors to be installed into the ATLAS Insertable B-Layer. An additional benefit is the feasibility of slim edges, which consist of a multiple ohmic column termination with an overall size as low as 100 µm. Eight batches with two different wafer layouts have been fabricated using this approach, and including several design options, among them the ATLAS 3D sensor prototypes compatible with the new read-out chip FE-I4. [ABSTRACT FROM PUBLISHER]

We present new results on the influence of radiation-induced damage on the electron Impact Ionization (I.I.) coefficient \alpha, suggesting a small but distinct reduction of \alpha at high fluence with respect to unirradiated silicon. Experiments on thick (1.5 \mum) and thin (1 \mum) epitaxial silicon samples confirm that such a reduction of \alpha is expected even in cases where impact ionization is not simply a field driven process because of strongly non local transport conditions. [ABSTRACT FROM AUTHOR]

The planned luminosity upgrade of the CERN LHC to the super LHC (sLHC) requires investigation of new radiation hard tracking detectors. Compared to the LHC, tracking detectors must withstand a 5–10 times higher radiation fluence. Promising radiation hard options are planar silicon detectors with n-side readout and silicon detectors in 3D technology, where columnar electrodes are etched into the silicon substrate. This article presents beam test measurements performed with planar and 3D n-in-p silicon strip detectors. The detectors were irradiated to different fluences, where the maximum fluence was 3\times 10^15 1 MeV neutron equivalent particles per square centimeter (neq/\rm cm^2) for the planar detectors and 2\times 10^15~neq/\rm cm^2 for the 3D detectors. In addition to signal measurements, charge sharing and resolution of both detector technologies are compared. An increased signal from the irradiated 3D detectors at high bias voltages compared to the signal from the unirradiated detector indicates that charge multiplication effects occur in the 3D detectors. At a bias voltage of 260 V, the 3D detector irradiated to 2\times 10^15~neq/\rm cm^2 yields a signal almost twice as high as the signal of the unirradiated detector. Only 30% of the signal of an unirradiated detector could be measured with the planar detector irradiated to 3\times 10^15~neq/\rm cm^2 at a bias voltage of 600 V, which was the highest bias voltage applied to this sensor. [ABSTRACT FROM AUTHOR]

Abstract: While the Large Hadron Collider (LHC) at CERN has started operation in autumn 2008, plans for a luminosity upgrade to the Super-LHC (sLHC) have already been developed for several years. This projected luminosity increase by an order of magnitude gives rise to a challenging radiation environment for tracking detectors at the LHC experiments. Significant improvements in radiation hardness are required with respect to the LHC. Using a strawman layout for the new tracker of the ATLAS experiment as an example, silicon strip detectors (SSDs) with short strips of 2–3cm length are foreseen to cover the region from 28 to 60cm distance to the beam. These SSD will be exposed to radiation levels up to , which makes radiation resistance a major concern for the upgraded ATLAS tracker. Several approaches to increasing the radiation hardness of silicon detectors exist. In this article, it is proposed to combine the radiation hard 3D-design originally conceived for pixel-style applications with the benefits of the established planar technology for strip detectors by using SSDs that have regularly spaced doped columns extending into the silicon bulk under the detector strips. The first 3D SSDs to become available for testing were made in the Single Type Column (STC) design, a technological simplification of the original 3D design. With such 3D SSDs, a small number of prototype sLHC detector modules with LHC-speed front-end electronics as used in the semiconductor tracking systems of present LHC experiments were built. Modules were tested before and after irradiation to fluences of . The tests were performed with three systems: a highly focused IR-laser with spot size to make position-resolved scans of the charge collection efficiency, an -source set-up to measure the signal levels for a minimum ionizing particle (MIP), and a beam test with 180GeV pions at CERN. This article gives a brief overview of the results obtained with 3D-STC-modules. [Copyright &y& Elsevier]

In this paper, we report on an Avalanche Photodiode (APD) fabricated in a standard 0.35-μm CMOS technology. The main electrooptical characteristics of the device are presented, showing a remarkably tow-noise factor if compared to other CMOS APDs. An estimation of the noise properties of a pixel based on the proposed photodiode with charge-amplifier readout is performed, showing that it could have an improved noise performance with respect to a standard photodiode-based pixel. [ABSTRACT FROM AUTHOR]

Abstract: Because of their superior radiation resistance, three-dimensional (3D) silicon sensors are receiving more and more interest for application in the innermost layers of tracker systems for experiments running in very high luminosity colliders. Their short electrode distance allows for both a low depletion voltage and a high charge collection efficiency even at extremely high radiation fluences. In order to fully understand the properties of a 3D detector, a thorough characterization of the signal formation mechanism is of paramount importance. In this work the shape of the current induced by localized and uniform charge depositions in a single-type column 3D detector is studied. A first row estimation is given applying the Ramo theorem, then a more complete TCAD simulation is used to provide a more realistic pulse shape. [Copyright &y& Elsevier]

Abstract: Recently, we presented a new 3D detector architecture aimed at simplifying the manufacturing process, making it more suitable for high-volume production. In particular, the proposed device features electrodes of one doping type only, e.g., n+ columns in a p-type substrate. In this paper we report on the fabrication at ITC-irst of the first batch of prototypes. The main issues related to the fabrication process along with preliminary results from the electrical characterization of different detectors and test structures are discussed. [Copyright &y& Elsevier]

This paper reports on the electrical characterization of the first prototypes of Geiger-Mode Avalanche Photodiodes (GM-APDs) and Silicon Photomultipliers (SiPMs) produced at ITC-irst, Trento. Both static and functional measurements have been performed in dark condition. The static tests, consisting in reverse and forward IV measurements, have been performed on 20 GM-APDs and 90 SiPMs. The breakdown voltage, the quenching resistance value and the current level have been proved to be very uniform. On the other hand, the analysis of the dark signals allowed the extraction of important properties such as the dark count rate, the gain, the after-pulse and optical cross-talk (in case of the SiPMs) rates. These parameters have been evaluated as a function of the bias voltage, showing trends perfectly compatible with the theory of the device. [ABSTRACT FROM AUTHOR]

Abstract: The 3D silicon radiation detectors are very promising devices to be used in environments requiring extreme radiation hardness, such as the super-LHC experiment at CERN. A drawback of this detector is the very long and non-standard fabrication process, which makes the mass production of these devices very critical. A possible simplification of the manufacturing process relies on a new type of 3D architecture, called 3D-single-type-column detector, that we have introduced in previous works. In this paper we report on the fabrication process of the first batch of detectors and on selected results from the electrical characterization of 3D test structures, covering leakage current, capacitance and breakdown voltage measurements. [Copyright &y& Elsevier]

Abstract: Prototypes of ionizing radiation detectors with internal signal amplification based on the bipolar transistor effect have been fabricated at ITC-irst (Trento, Italy). Results from the electrical characterization and preliminary functional tests of the devices have been previously reported. Here, we present a more detailed investigation of the performance of this type of detector, with particular attention to their noise and rate limits. Measurements of the signal waveform and of the gain versus frequency dependence are performed by illuminating the devices with, respectively, pulsed or sinusoidally modulated IR light. Pulse height spectra of X-rays from an source have been taken with very simple front-end electronics (an LF351 operational amplifier) or by directly reading with an oscilloscope the voltage drop across a load resistor connected to the emitter. An equivalent noise charge (referred to input) of 380 electrons r.m.s. has been obtained with the first setup for a small device, with an active area of and a depleted thickness of 0.6mm. The corresponding power dissipation in the BJT was . The performance limitations of the devices are discussed. [Copyright &y& Elsevier]

Due to their low depletion voltage, even after high particle fluences, improved tracking precision and momentum resolution, and reduced material budget, thin substrates are one of the possible choices to provide radiation hard detectors for future high energy physics experiments. In the framework of the CERN RD50 Collaboration, we have developed PIN diode detectors on membranes obtained by locally thinning the silicon substrate by means of TMAH etching from the wafer backside. Diodes of different shapes and sizes have been fabricated on 50-μm and 100-μm thick membranes and tested, showing a low leakage current (of 300 nA/cm³) and a very low depletion voltage (in the order of 1 V for the 50 μpm membrane) before irradiation. Radiation damage tests have been performed with 58 MeV lithium (Li) ions up to the fluence of 1014 Li/cm² in order to determine the depletion voltage and leakage current density increase after irradiation. Charge collection efficiency tests carried out with a β- particle source have been performed on both nonirradiated devices and samples irradiated upto 1.8 × 1013 Li/cm². Results reported here confirm the advantages of thinned diodes with respect to standard 300-μm thick devices in terms of low depletion voltage and high charge collection efficiency. [ABSTRACT FROM AUTHOR]

We report on the electrical behavior of termination structures for silicon diodes irradiated with high-energy particles. In particular, the analysis is focused on samples featuring an all-P-type (APT) termination structure that has already been proved to yield excellent long-term stability performance. The radiation hardness of these structures is compared to that of more common reference devices. In order to characterize various radiation conditions, tests were performed using protons, neutrons, and high-energy electrons with different influences up to values causing substrate type inversion. We verified that the APT samples remain functional in all the considered situations, their operational limit being comparable to that of the other devices. [ABSTRACT FROM AUTHOR]

Abstract: 3D silicon radiation detectors offer many advantages over planar detectors, including improved radiation tolerance and faster charge collection time. We proposed a new 3D architecture (referred to as 3D-stc), which features columnar electrodes of one doping type only, thus, allowing a considerable simplification of the manufacturing process. In this paper, we report selected results from the electrical characterization of 3D diodes fabricated with this technology, along with preliminary results on the charge collection efficiency of these devices. [Copyright &y& Elsevier]

Abstract: We report on the results from the production of 600 double-sided silicon microstrip detectors for the ALICE experiment. We present the fabrication process and some selected results from the electrical characterization of detectors and test structures. The large amount of experimental data allowed a statistically relevant analysis to be performed. The main technological aspects related to production yield optimization will also be addressed. [Copyright &y& Elsevier]

Looking forward to future High Luminosity LHC experiments, efforts to develop new tracking detectors are increasing. A common approach to improve track reconstruction efficiency in high pile-up conditions is to add time measurement per pixel with resolution smaller than 50 ps. Different sensor technologies are under development in order to achieve those performances, like low gain avalanche diodes and 3D sensors. 3D sensors are characterized by very fast charge collection times, but present some critical issues in timing due to their electrode configurations. The presence of zero electric field volumes inside the electrodes themselves and low electric field regions between same sign electrodes causes that the 3D sensor technology presents potentially a large time walk contribution which negatively affects time resolution. In order to reduce this error drastically, a detailed study based mostly on simulation has been done with main focus on the exploration for a timing optimized 3D sensor electrode configuration. To have a more detailed view of the timing performances, sensor operation was also simulated, using TCAD and other simulation tools developed specific for this application, and the results analysed. In this presentation a detailed overview of the modelling and simulation activity as well as their results, including also future steps will be presented. The output of this studies defines the optimal sensor layout for timing applications. [ABSTRACT FROM AUTHOR]