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The ATLAS collaboration is designing the all-silicon Inner Tracker (ITk) that will operate in the HL-LHC replacing the current design. The silicon microstrip sensors for the barrel and the endcap regions in the ITk are fabricated in 6 inch, p-type, float-zone wafers, where large-area strip sensor designs are laid out together with a number of miniature sensors. The radiation tolerance and specific system issues like the need for slim edge of 450 μm have been tested with square shaped sensors intended for the barrel part of the tracker. This work presents the design of the first full size silicon microstrip sensor for the endcap region with a slim edge of 450 μm. The strip endcaps will consist of several wheels with two layers of silicon strip sensors each. The strips have to lie along the azimuthal direction, apart from a small stereo angle rotation (20 mrad on each side, giving 40 mrad total) for measuring the second coordinate of tracks. This stereo angle is built into the strip layout of the sensor and, in order to avoid orphan strips, the sensor edges are inclined by the stereo angle. On top of this, the top and bottom edges are designed as arcs to have equal length strips. Together with the design of this new Stereo Annulus sensor, we will report on the initial measurements of the leakage current as a function of bias voltage, after dicing, and the depletion voltage., The research was supported and financed in part by Canada Foundation for Innovation, the National Science and Engineering Research Council (NSERC) of Canada under the Research and Technology Instrumentation (RTI) grant SAPEQ-2016-00015; the Spanish Ministry of Economy and Competitiveness through the Particle Physics National Program, ref. FPA2015-65652-C4-4-R (MINECO/FEDER, UE), and co-financed with FEDER funds; and USA Department of Energy, Grant DE-SC0010107.

Journal of Instrumentation 15(09), P09004 (2020). doi:10.1088/1748-0221/15/09/P09004, For the Phase-II Upgrade of the ATLAS Detector [1], its Inner Detector, consisting of silicon pixel, silicon strip and transition radiation sub-detectors, will be replaced with an all new 100% silicon tracker, composed of a pixel tracker at inner radii and a strip tracker at outer radii. The future ATLAS strip tracker will include 11,000 silicon sensor modules in the central region (barrel) and 7,000 modules in the forward region (end-caps), which are foreseen to be constructed over a period of 3.5 years. The construction of each module consists of a series of assembly and quality control steps, which were engineered to be identical for all production sites. In order to develop the tooling and procedures for assembly and testing of these modules, two series of major prototyping programs were conducted: an early program using readout chips designed using a 250 nm fabrication process (ABCN-250) [2,2] and a subsequent program using a follow-up chip set made using 130 nm processing (ABC130 and HCC130 chips). This second generation of readout chips was used for an extensive prototyping program that produced around 100 barrel-type modules and contributed significantly to the development of the final module layout. This paper gives an overview of the components used in ABC130 barrel modules, their assembly procedure and findings resulting from their tests., Published by Inst. of Physics, London

A significant aspect of the Phase-II Upgrade of the ATLAS detector is the replacement of the current Inner Detector with the ATLAS Inner Tracker (ITk). The ATLAS ITk is an all-silicon detector consisting of a pixel tracker and a strip tracker. Sensors for the ITk strip tracker have been developed to withstand the high radiation environment in the ATLAS detector after the High Luminosity Upgrade of the Large Hadron Collider at CERN, which will significantly increase the rate of particle collisions and resulting particle tracks. During their operation in the ATLAS detector, sensors for the ITk strip tracker are expected to accumulate fluences up to 1.6 x 10^15 n_eq/cm^2 (including a safety factor of 1.5), which will significantly affect their performance. One characteristic of interest for highly irradiated sensors is the shape and homogeneity of the electric field inside its active area. For the results presented here, diodes with edge structures similar to full size ATLAS sensors were irradiated up to fluences comparable to those in the ATLAS ITk strip tracker and their electric fields mapped using a micro-focused X-ray beam (beam diameter 2x3 {\mu}m^2). This study shows the extension and shape of the electric field inside highly irradiated diodes over a range of applied bias voltages. Additionally, measurements of the outline of the depleted sensor areas allow a comparison of the measured leakage current for different fluences with expectations for the corresponding active areas., Comment: published in the proceedings of the 12th International "Hiroshima" Symposium on the Development and Application of Semiconductor Tracking Detectors (HSTD12)

A new vertical JFET transistor has been recently developed at the IMB-CNM, taking advantage of a deep-trenched 3D technology to achieve vertical conduction and low switch-off voltage. The silicon V-JFET transistors were mainly conceived to work as rad-hard protection switches for the renewed HV powering scheme (HV-MUX) of the ATLAS upgraded tracker. This work presents the features of the first batch of V-JFETs produced at the IMB-CNM clean room, together with the results of a full pre-irradiation characterization of the fabricated prototypes. Details of the technological process are provided and the outcome quality is also evaluated with the aid of reverse engineering techniques. Concerning the electrical performance of the prototypes, promising results were obtained, already meeting most of the HV-MUX specifications, both at room and below-zerotemperatures.

The ATLAS experiment is going to replace the current Inner Detector with an all new inner tracker (ITk) in the ATLAS detector for HL-LHC at CERN. Silicon strip detectors cover the outer layers of the barrel and the endcap sections. We have designed and fabricated a prototype single-sided n + -in-p AC-coupled silicon strip sensor for the outer barrel layer with long strips (LS), ATLAS17LS. It is of the maximum allowable size to fit in a 6-in. silicon wafer, with an outer dimension of 9.80 (width) × 9.76 (length) cm 2 . The sensor features two rows of LS strip segments, 4.83 cm strip length per segment, a strip pitch of 75.5 μ m , and a slim edge design. We have implemented technology for high voltage operation of up to 1000 V, with a good signal collection after irradiation fluence of 5.6 × 1014 n eq ∕ cm 2 at the end of HL-LHC operation. We had two objectives for the ATLAS17LS fabrication: qualification of the sensor design and fabrication quality, and providing an adequate number of the sensors for prototyping the building blocks of the strip detector. The sensors were fabricated in 3 batches by HPK with standard wafers from the foundry (320 μ m physical thickness). Additional 10 sensors were fabricated with a thinner active thickness of 240 μ m to investigate the influence of active thickness on charge collection. Another additional 5 sensors, with special passivation to investigate the influence of passivation on humidity sensitivity. The visual inspection of fabricated sensors revealed an inadequacy that the designed metal width of 10 μ m was too narrow. The initial measurements by the vendor showed that the sensors fulfilled the specifications: onset voltages of Microdischarge V M D above the operation voltage V O P (700 V for the 1st and 2nd batches; 500 V for the 3rd batch, which has improved the yield), leakage currents of 0.1 μ A/cm 2 at V O P , full depletion voltages V F D 330 V, and rates of bad strips 1%.

Silicon strip sensors for the ATLAS Inner Tracker (ITk) have been designed to provide reliable particle detection in the high-radiation environment of the High-Luminosity Large Hadron Collider. One important design criterion for their development is the minimization of inactive sensor areas, which affect the hermiticity of particle detection inside the detector. In previous measurements of ATLAS silicon strip sensors, the charge-collecting area of individual strip implants has been mapped and found to agree with the sensor strip pitch and strip length. For strip implants next to the sensor bias ring, the extent of their charge-collecting area towards the inactive sensor area was previously unknown, which limited the accuracy of both overall detector hermiticity estimates and the position resolution for particle detection at the sensor edge. Therefore, measurements were conducted to map the area of charge collection for sensor strips at the edge of the active sensor area using a micro-focused X-ray beam. This publication presents measurements showing the extent of charge collection in the edge strips of silicon strip sensors for two generations of ATLAS ITk strip sensor modules. The measurements confirmed that charge deposited in a strip implant that is neither connected nor grounded leads to capacitive coupling to the adjacent strip, where it is indistinguishable from a hit in that strip.

EASY, a plug-and-play educational system, is portable, compact and a complete system for micro-strip sensor characterization. Ideal for making basic or complex experiments. It is based on the Classic Alibava System [1], largely used within the CERN community to test micro-strip detectors for particle experiments. The system can be configured to work with pulsed laser light or radioactive sources. The aim of this system is to illustrate students in the operation of a silicon strip detectors The components of the EASY systems are the Control Unit and the Sensor Unit. The Control Unit is the heart of the system communicating with the Sensor Unit and the Computer software. It contains the Data Acquisition Control and it is also in charge of processing of the sensor data and trigger inputs. In addition, it contains an adjustable Hight Voltage unit for micro-strip sensor bias, with voltage and current display and includes the laser source. The Control Unit communicates with computer software via USB. The Sensor Unit accommodate a p-on-n silicon micro-strip sensor segmented in 128 strips. EASY comes with an activity book where the students, through 10 exercises, are introduced in the main concepts and functionalities of micro-strip silicon detectors, used in the actual particle physic experiments. The book also provides a full description of the EASY device and the data Acquisition system.

The high luminosity upgrade of the Large Hadron Collider, foreseen for 2027, requires the replacement of the ATLAS Inner Detector with a new all-silicon Inner Tracker (ITk). The expected total integrated luminosity of 4000 fb − 1 means that the strip part of the ITk detector will be exposed to a large radiation fluence of up to Φ e q = 1.6 × 1015 1 MeV n e q /cm and an ionizing dose of 0.66 MGy, including a safety factor of 1.5. Radiation-hard n + -in-p micro-strip sensors for use in the ITk have been developed by the ATLAS ITk Strip Sensor collaboration and produced by Hamamatsu Photonics K.K. In this paper, the results obtained from the electrical characterization of the latest barrel ATLAS17LS sensor prototype, before and after irradiation, are shown. Surface properties of the long-strip barrel, full-sized and miniature sensors have been studied before and after proton, neutron and gamma irradiation up to the maximal fluences and radiation doses specified for the ITk Strip tracker. Sensors have been irradiated by protons at CYRIC, Tohoku University (Japan), the Proton Irradiation Facility at CERN, Karlsruhe Inst. Tech. (Germany) and at the University of Birmingham (UK), by neutrons from the Ljubljana TRIGA reactor (Slovenia) and by gamma rays from the 60 Co source in UJP Praha (Czech Republic). It has been verified that the surface radiation damage does not influence the sensor functionality. The breakdown voltage is well above the maximum operational voltage. All the tested surface parameters, such as the inter-strip resistance and capacitance, coupling capacitance and bias resistance satisfy the ATLAS ITk specifications for strip sensors.

The ATLAS community is facing the last stages prior to the production of the upgraded silicon strip Inner Tracker for the High-Luminosity Large Hadron Collider. An extensive Market Survey was carried out in order to evaluate the capability of different foundries to fabricate large area silicon strip sensors, satisfying the ATLAS specifications. The semiconductor manufacturing company, Infineon Technologies AG, was one of the two foundries, along with Hamamatsu Photonics K.K., that reached the last stage of the evaluation for the production of the new devices. The full prototype wafer layout for the participation of Infineon, called ATLAS17LS-IFX, was designed using a newly developed Python-based Automatic Layout Generation Tool, able to rapidly design sensors with different characteristics and dimensions based on a few geometrical and technological input parameters. This work presents the layout design process and the results obtained from the evaluation of the new Infineon large area sensors before and after proton and neutron irradiations, up to fluences expected in the inner layers of the future ATLAS detector.

The production of the strip sensors for the ATLAS Inner Tracker (ITk) will start in 2020. Nearly 22,000 large area sensors will be produced over a period of about five years by Hamamatsu Photonics K.K. (HPK). The institutes involved in the sensor development and production are committed to deliver and maintain the highest quality sensors for the experiment. A Quality Assurance (QA) strategy has been prepared to be carried out during the whole production period. Once the process has been characterized as providing the required pre-irradiation specifications and the proper radiation hardness, the onus is on the manufacturer to rigidly stick to that qualified process. Still, sample testing with specific device-element structures and irradiation of devices should be implemented by the ITk sensor collaboration. A detailed irradiation and testing plan has been prepared by the ATLAS-ITk Collaboration, together with a newly designed test chip with specific structures to monitor different key technological and device parameters during the whole production. The tests and irradiations will be carried out on a sample basis. In order to have a practical methodology, samples from alternating batches will be sent for irradiations with protons, neutrons and gammas, and then tested in order to check that the characteristics remain within specifications. The detailed plan and the design and test methods for the structures in the test chip are presented here.

The production of large area sensors is one of the main challenges that the ATLAS collaboration faces for the new Inner-Tracker full-silicon detector. During the prototype fabrication phase for the High Luminosity Large Hadron Collider upgrade, several ATLAS institutes observed indications of humidity sensitivity of large area sensors, even at relative humidities well below the dew point. Specifically, prototype Barrel and End-Cap silicon strip sensors fabricated in 6-inch wafers manifest a prompt decrease of the breakdown voltage when operating under high relative humidity, adversely affecting the performance of the sensors. In addition to the investigation of these prototype sensors, a specific fabrication batch with special passivation is also studied, allowing for a deeper understanding of the responsible mechanisms. This work presents an extensive study of this behaviour on large area sensors. The locations of the hotspots at the breakdown voltage at high humidity are revealed using different infrared thermography techniques. Several palliative treatments are attempted, proving the influence of sensor cleaning methods, as well as baking, on the device performance, but no improvement on the humidity sensitivity was achieved. Furthermore, a study of the incidence of the sensitivity in different batches is also presented, introducing a hypothesis of the origins of the humidity sensitivity associated to the sensor edge design, together with passivation thickness and conformity. Several actions to be taken during sensor production and assembly are extracted from this study, in order to minimize the impact of humidity sensitivity on the performance of large area silicon sensors for High Energy Physics experiments.

The planned upgrade of the Large Hadron Collider, the HL-LHC, requires the development of improved tracking silicon sensors for the main CERN experiments. These devices must fulfil the specifications established by the different detectors for the adverse HL-LHC working conditions, in order to guarantee the proper performance of the tracking systems during the lifetime of the experiments. In the framework of the ATLAS Inner-Tracker sensor Market Survey, a prototype strip sensor layout has been designed by the collaboration, and fabricated in 6-inch substrates by Infineon Technologies AG. This work presents a set of test structures included in this prototype, capable to evaluate key device and technological parameters as strip implant resistivity, bias resistance, coupling capacitance, surface currents, or the influence of the sensor edge design in device breakdown voltage. A complete analysis of these parameters before and after proton and gamma irradiations, up to fluences and doses similar to the ones expected in the future HL-LHC experiments, is presented. This study shows the relevance of microelectronic test structures in the development of technologies of tracking silicon sensors for High Energy Physics experiments.

We report on design and performance of new strip sensors for the Heavy Photon Search (HPS) experiment. The sensors feature a slim edge implementation using the Scribe–Cleave–Passivate (SCP) method. The slim edge design has allowed the introduction of a new layer closer to the target, which increased the tracking acceptance and vertex precision, improving physics reach of the experiment. We describe the production, testing, and operational experience with the new sensors.

The ATLAS detector community is entering in the final stages of sensor development for the future upgrade of the Large Hadron Collider (LHC). An increase by an order of magnitude of the LHC luminosity, up to 1035 cm−2s−1, will lead to an increased radiation dose delivered to the detector, especially for the devices located in the Inner Tracker. In 2018, an experimental study of the damages induced by a beam-loss over silicon strip detectors was done in the High-Radiation to Materials facility at CERN. A progressive number of proton bunches was extracted from the CERN Super Proton Synchrotron, and focused directly over the strip sensor, in order to emulate the large amount of charge typically generated in a beam-loss failure. This work presents the results obtained during this experiment, showing that Punch-Through Protection effectively protects the AC-coupling capacitors of the silicon sensors from large charge accumulations, but still this scenario could induce damages on the read-out electronics.

Electronic devices operating in harsh radiation environments must withstand high radiation levels with minimal performance degradation. Recent experiments on the radiation hardness of a new vertical p-type JFET power switch have shown a significant reduction of forward drain current under non-ionizing conditions. In this work, atomistic simulations are used to study the impact of irradiation-induced displacement damage on forward characteristics. Damage models have been updated to produce a better description of damage-dopant interactions at RT. Our results show that excess self-interstitials produced by irradiation deactivate a significant amount of B atoms, thus reducing the effective dopant concentration.

Journal of Instrumentation 14(03), P03024 - P03024 (2019). doi:10.1088/1748-0221/14/03/P03024, For the Phase-II Upgrade of the ATLAS detector at CERN, the current ATLAS Inner Detector will be replaced with the ATLAS Inner Tracker (ITk). The ITk will be an all-silicon detector, consisting of a pixel tracker and a strip tracker. Sensors for the ITk strip tracker are required to have a low leakage current up to bias voltages of −500 V to maintain a low noise and power dissipation. In order to minimise sensor leakage currents, particularly in the high-radiation environment inside the ATLAS detector, sensors are foreseen to be operated at low temperatures and to be manufactured from wafers with a high bulk resistivity of several kΩ·cm. Simulations showed the electric field inside sensors with high bulk resistivity to extend towards the sensor edge, which could lead to increased surface currents for narrow dicing edges. In order to map the electric field inside biased silicon sensors with high bulk resistivity, three diodes from ATLAS silicon strip sensor prototype wafers were studied with a monochromatic, micro-focused X-ray beam at the Diamond Light Source (Didcot, U.K.). For all devices under investigation, the electric field inside the diode was mapped and its dependence on the applied bias voltage was studied., Published by Inst. of Physics, London

For silicon strip sensors, the tracking information specifications can lead to challenging requirements for wire bonding. A common strategy is to use external pitch adapters to facilitate this step in the production of detector modules. A novel approach previously discussed in [1], is to implement the pitch adapters in the sensor, by embedding a second layer of metal tracks. The use of these embedded pitch adapters (EPAs) decouples the bond pad layout of the sensor from its implant layout by moving the adaption to the sensor production step. This solution, however, can yield the risk of performance losses due to the increase of inter-strip capacitance, or unwanted capacitive coupling between the metal layers (cross-talk) or the silicon bulk and the second metal layer (pick-up). In the prototyping stage of the ATLAS tracker end-cap upgrade, where different bond-pad layouts on sensor and readout chip lead to extremely challenging wire-bonding conditions, sensors with different geometries of EPA implementations have been produced at Centro Nacional de Microelectronica (IMB-CNM, CSIC), Barcelona, Spain. In order to study the influence of the EPA on the sensor performance, these sensors, built into a prototype detector module, were investigated in an x-ray beam. In this contribution, results of a study on the pick-up phenomenon in sensor regions with a high density of second-metal-layer tracks are presented. The performed measurements were taken in 15~$\mu$m by 10~$\mu$m steps with a micro-focussed 15~keV photon beam which allows resolution of the details of the EPA geometry. The amount of signal degradation in primary strips in the presence of second-metal tracks as well as the size of the pick-up-induced signal in the deployed test setup are quantified. Recommendations regarding the geometry of the embedded pitch adapter are given, resulting in limits and opportunities for future applications. [1] M. Ullan et al., Embedded Pitch Adapters: a High-Yield Interconnection Solution for Strip Sensors, NIM A, 2016

An increasing demand for power electronic devices able to be operative in harsh radiation environments is now taking place. Specifically, in High Energy Physics experiments the required power devices are expected to withstand very high radiation levels which are normally too hard for most of the available commercial solutions. In this context, a new vertical junction field effect transistor (JFET) has been designed and fabricated at the Instituto de Microelectrónica de Barcelona, Centro Nacional de Microelectrónica (IMB-CNM, CSIC). The new silicon V-JFET devices draw upon a deep-trenched technology to achieve volume conduction and low switch-off voltage, together with a moderately high voltage capability. The first batches of V-JFET prototypes have been already fabricated at the IMB-CNM clean room, and several aspects of their design, fabrication and the outcome of their characterization are summarized and discussed in this paper. Radiation hardness of the fabricated transistors have been tested both with gamma and neutron irradiations, and the results are also included in the contribution., The authors would like to heartily thank the Clean Room staff of the IMB-CNM for their dedicated work and kind availability. This work is supported and financed in part by the Spanish Ministry of Economy and Competitiveness through the Particle Physics National Program, ref. FPA2014-55295-C3-2-R and FPA2015-65652-C4-4-R (MINECO/FEDER, UE), and co-financed with FEDER funds and the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 654158. The work is also partially supported by the Generalitat de Catalunya (2014-SGR-1596). The authors want to thank Pedro Valdivieso and co-workers at NAYADE facility (CIEMAT) and the staff on the TRIGA nuclear reactor facilities (JSI), for their efficiency and dedication in performing the managing and irradiation of our devices., We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI).

Technological solutions for the transfer to large area microstrip radiation silicon sensors are presented for the upgrade of the ATLAS detector. A new Automatic Layout Generation Tool has been developed to easily adapt the design of the sensors, investigating also the fabrication processes involved in 6-inch wafer technology. Inter-strip and radiation hardness characterization of prototype sensors is presented, showing an agreement with the new specifications. Embedded Pitch Adaptor concept is studied as a solution for the sensor/readout interconnection for the forthcoming ATLAS Upgrade.

Journal of Instrumentation 12(05), P05015 - P05015 (2017). doi:10.1088/1748-0221/12/05/P05015, For the High-Luminosity upgrade of the Large Hadron Collider an increased instantaneous luminosity of up to 7.5 ⋅ 10$^{34}$ cm$^{−2}$ s$^{−1}$, leading to a total integrated luminosity of up to 3000 fb$^{−1}$, is foreseen. The current silicon and transition radiation tracking detectors of the ATLAS experiment will be unable to cope with the increased track densities and radiation levels, and will need to be replaced. The new tracking detector will consist entirely of silicon pixel and strip detectors. In this paper, results on the development and tests of prototype components for the new silicon strip detector in the forward regions (end-caps) of the ATLAS detector are presented. Flex-printed readout boards with fast readout chips, referred to as hybrids, and silicon detector modules are investigated. The modules consist of a hybrid glued onto a silicon strip sensor. The channels on both are connected via wire-bonds for readout and powering. Measurements of important performance parameters and a comparison of two possible readout schemes are presented. In addition, the assembly procedure is described and recommendations for further prototyping are derived., Published by Inst. of Physics, London

This paper introduces a new concept of silicon radiation detector with intrinsic multiplication of the charge, called Low Gain Avalanche Detector (LGAD). These new devices are based on the standard Avalanche Photo Diodes (APD) normally used for optical and X-ray detection applications. The main differences to standard APD detectors are the low gain requested to detect high energy charged particles, and the possibility to have fine segmentation pitches: this allows fabrication of microstrip or pixel devices which do not suffer from the limitations normally found [1] in avalanche detectors. In addition, a moderate multiplication value will allow the fabrication of thinner devices with the same output signal of standard thick substrates. The investigation of these detectors provides important indications on the ability of such modified electrode geometry to control and optimize the charge multiplication effect, in order to fully recover the collection efficiency of heavily irradiated silicon detectors, at reasonable bias voltage, compatible with the voltage feed limitation of the CERN High Luminosity Large Hadron Collider (HL-LHC) experiments [2] . For instance, the inner most pixel detector layers of the ATLAS tracker will be exposed to fluences up to 2×10 16 1 MeV n eq /cm 2 , while for the inner strip detector region fluences of 1×10 15 n eq /cm 2 are expected. The gain implemented in the non-irradiated devices must retain some effect also after irradiation, with a higher multiplication factor with respect to standard structures, in order to be used in harsh environments such those expected at collider experiments.

The possible physical mechanism of the anomalous recovery effect in SiGe bipolar transistors is described. The qualitative analysis of saturated oxide trapped charge and interface trap densities at very high total doses as a function of dose rate affords an explain of decreasing excess base current and increasing current gain during further low dose rate irradiation.

AC-coupled silicon strip sensors can be damaged in case of a beam loss due to the possibility of a large charge accumulation in the bulk, developing very high voltages across the coupling capacitors which can destroy them. Punch-through structures are currently used to avoid this problem helping to evacuate the accumulated charge as large voltages are developing. Nevertheless, previous experiments, performed with laser pulses, have shown that these structures can become ineffective in relatively long strips. The large value of the implant resistance can effectively isolate the “far” end of the strip from the punch-through structure leading to large voltages. We present here our developments to fabricate low-resistance strip sensors to avoid this problem. The deposition of a conducting material in contact with the implants drastically reduces the strip resistance, assuring the effectiveness of the punch-through structures. First devices have been fabricated with this new technology. Initial results with laser tests show the expected reduction in peak voltages on the low resistivity implants. Other aspects of the sensor performance, including the signal formation, are not affected by the new technology.

A test beam telescope has been built using the ALIBAVA system to drive its data acquisition. The basic telescope planes consist of four XYT stations. Each station is built from a detector board with two strip sensors, mounted one in each side (strips crossing at 90°). The ensemble is coupled to an ALIBAVA daughter board. These stations act as reference frame and allow a precise track reconstruction. The system is triggered by the coincidence signal of the two scintillators located up and down stream. The telescope can hold several devices under tests. Each ALIBAVA daughter board is linked to its corresponding mother board. The system can hold up to 16 mother boards. A master board synchronizes and controls all the mother boards and collects their data. The off-line analysis software has been developed to study the charge collection, cluster width, tracking efficiency, resolution, etc., of the devices under test. Moreover, the built-in ALIBAVA TDC allows the analysis of the time profile of the device signal. The ALIBAVA telescope has been successfully operated in two test runs at the DESY and CERN-SPS beam lines.

In the current ATLAS tracker modules, sensor bonding pads are placed on their corresponding strips and oriented along the strips. This creates a difference in pitch and orientation between sensor bond pads and readout electronics bond pads. Therefore, a pitch adapter (PA), or “fan-in”, is needed. The purpose of these PA is the electrical interconnection of every channel from the detector bonding pads to the read-out chips, adapting the different pad pitch. Our new approach is to build those PAs inside the sensor; this is what we call Embedded Pitch Adapters. The idea is to use an additional metal layer in order to define a new group of pads, connected to the strips via tracks with the second metal. The embedded PAs have been fabricated on 4-in. prototype sensors for the ATLAS-Upgrade Endcap Tracker to test their performance and suitability. The tests confirm proper fabrication of the second metal tracks, and no effects on detector performance. No indication of cross-talk between first and second metal channels has been observed. A small indication of possible signal pick-up from the bulk has been observed in a few channels, which needs to be further investigated.

In the year 2022 an upgrade of the Large Hadron Collider (LHC) is planned to increase the luminosity such that an integrated luminosity of L int ∼ 3000 fb − 1 can be accumulated by 2030 [1] . The radiation damage of the present inner tracker at this date and the high track density of the High Luminosity LHC (HL-LHC) require an upgrade of the inner tracker of the ATLAS (A Toroidal LHC ApparatuS) experiment. A new integration concept will be used: the readout electronics is directly glued on the strip surface of the silicon sensors and the sensors are glued to a support structure. For the barrel region this structure is referred to as a Stave and for the end-cap region it is referred to as a Petal. For tests a smaller version, the Petalet, will be build with two design concepts. In this article the construction method is explained and first hybrid test results for one Petalet sensor are presented.

A new comprehensive method for assessing Enhanced Low Dose Rate Sensitivity (ELDRS) in bipolar transistors to be used for very high total doses is applied to an advanced SiGe HBT technology for its use in the ATLAS Upgrade at CERN. Conventional ELDRS assessment methods are combined with switched experiments (high/low dose rate), providing a way to verify the presence of ELDRS at very high doses in reasonable irradiation time. Additionally, an anomalous damage recovery has been found in transistors with saturated damage after further low dose rate irradiations.

The Large Hadron Collider (LHC) recorded its first collisions during the last months of 2009. By 2020 a two-stage upgrade of the accelerator complex, the High Luminosity LHC (HL-LHC), will increase the instantaneous luminosities up to a factor of ten compared to the current design. The particle fluxes at ATLAS will increment substantially with special impact on the inner tracking detector which will be subjected to large occupancies and radiation damage. In order to cope with the higher instantaneous luminosities ATLAS will upgrade its current Inner Detector (ID) in two phases, first by introducing a new pixel layer (IBL) mounted directly on the beam pipe, and later by completely replacing the current ID with several layers of semiconductor detectors (pixels and strips). The upgrades to the ATLAS ID require the development of new silicon technologies, since the current planar pixel sensors are not suitable for the expected radiation doses at small radii. For these inner detector layers, the most promising technology is the so-called 3D sensor, while improved planar sensors are considered for the external layers. Silicon detectors with cylindrical electrodes offer advantages over standard planar sensors mainly because they are more radiation hard. 3D detectors with the double sided geometry have been fabricated at IMB-CNM clean room facilities. The layouts fits the new pixelated readout chip FE-I4 developed by the ATLAS collaboration.

Nuclear instruments & methods in physics research / A 833, 226 - 232(2016). doi:10.1016/j.nima.2016.07.023, The new silicon microstrip sensors of the End-cap part of the HL-LHC ATLAS Inner Tracker (ITk) present a number of challenges due to their complex design features such as the multiple different sensor shapes, the varying strip pitch, or the built-in stereo angle. In order to investigate these specific problems, the “petalet” prototype was defined as a small End-cap prototype. The sensors for the petalet prototype include several new layout and technological solutions to investigate the issues, they have been tested in detail by the collaboration. The sensor description and detailed test results are presented in this paper. New software tools have been developed for the automatic layout generation of the complex designs. The sensors have been fabricated, characterized and delivered to the institutes in the collaboration for their assembly on petalet prototypes. This paper describes the lessons learnt from the design and tests of the new solutions implemented on these sensors, which are being used for the full petal sensor development. This has resulted in the ITk strip community acquiring the necessary expertise to develop the full End-cap structure, the petal., Published by North-Holland Publ. Co., Amsterdam

The IMB-CNM (Barcelona) has developed a new vertical JFET (V-JFET) technology with the purpose of working as rad-hard switches in the HV powering scheme of the upgraded ATLAS tracker. The design of the new transistors draws upon a deep-trenched 3D technology to achieve vertical conduction and low switch-off voltage. These features prospect suitable radiation hardness for the application. The first V-JFET prototypes are now fabricated and characterized, with very promising results already meeting the application requirements. A compilation of the simulated and measured performance is shown in the contribution. To evaluate the radiation hardness, gamma irradiation has been performed and the main results are presented here.

The design and technology of the silicon strip detector modules for the Semiconductor Tracker (SCT) of the ATLAS experiment have been finalised in the last several years. Integral to this process has been the measurement and verification of the tracking performance of the different module types in test beams at the CERN SPS and the KEK PS. Tests have been performed to explore the module performance under various operating conditions including detector bias voltage, magnetic field, incidence angle, and state of irradiation up to 3×1014 protons per square centimetre. A particular emphasis has been the understanding of the operational consequences of the binary readout scheme. © 2004 Elsevier B.V. All rights reserved.

Stellar explosions are relevant and interesting astrophysical phenomena. Since long ago we have been working on the characterization of novae and supernovae in X and gamma-rays, with the use of space missions. We have also been involved in feasibility studies of future instruments in the energy range from several keV up to a few MeV, in collaboration with other research institutes. High sensitivities are essential to perform detailed studies of cosmic explosions and cosmic accelerators, e.g., Supernovae and Classical Novae. In order to fulfil the combined requirement of high detection efficiency with good spatial and energy resolution, an initial module prototype based on CdTe pixel detectors is being developed. The detector dimensions are 12.5mm x 12.5mm x 2mm with a pixel pitch of 1mm x 1mm. Two kinds of CdTe pixel detectors with different contacts have been tested: ohmic and Schottky. Each pixel is bump bonded to a fanout board made of Sapphire substrate and routed to the corresponding input channel of the readout VATAGP7.1 ASIC, to measure pixel position and pulse height for each incident gamma-ray photon. The study is complemented by the simulation of the CdTe module performance using the GEANT 4 and MEGALIB tools, which will help us to optimise the detector design. We will report on the spectroscopy characterisation of the CdTe detector module as well as the study of charge sharing.

Due to the increasing interest on laterally diffused MOS (LDMOS) transistors as a part of power electronics in the high energy physics (HEP) experiments, the effect of total ionising dose (TID) on their electrical performances has been experimentally measured. The analysis of the experimental results requires the aid of physics-based simulations to study the impact of TID effects on the LDMOS drift oxide layer. In this work, a simulation methodology is developed in order to analyse the changes in the electric field distribution as a consequence of the TID induced trapped charge, and its relationship with the technological parameters and the bias conditions. The simulation results are compared with the experimental data.

SiGe BiCMOS technologies are one of the proposed options for the front-end readout electronics of the detectors in the middle region of the ATLAS-Upgrade. The radiation hardness of the SiGe bipolar transistors is being assessed for this application through irradiations with different particles. Biasing conditions during irradiation experiments of bipolar transistors or circuits have an influence on the damage and there is a risk of erroneous results. We have performed several irradiation experiments of SiGe devices in different bias conditions. We have observed a systematic trend in gamma irradiations, showing a smaller damage in transistors irradiated biased compared to those irradiated with shorted or floating terminals. These effects have not been observed in neutron irradiations.

Proton irradiation results are shown here for three different SiGe:C HBT technologies from IHP Microelectronics. High damages are observed although the transistors remain usable for their application on the Super-LHC. Considerations on the ionization and displacement effects additivity are also presented in order to validate parameterized experiments. This study shows a reasonable agreement between proton irradiations and previous gamma and neutron irradiations.

In this study we present the results of radiation hardness studies performed on three different SiGe:C BiCMOS technologies from Innovation for High Performance Microelectronics (IHP) for their application in the Super-Large Hadron Collider (S-LHC). We performed gamma, neutron and proton irradiations on the bipolar section of these technologies, in order to consider ionization and atomic displacement damage on electronic devices. Results show that transistors from the IHP BiCMOS technologies remain functional after the radiation levels expected in the inner detector (ID) of the ATLAS Upgrade experiment. These technologies are one of the candidates to constitute the analog part of the Front-End chip in the ATLAS-upgrade experiment, in the S-LHC.

A novel ultra-thin silicon detector called U3DTHIN has been designed and built for applications that range from Neutral Particle Analyzers (NPA) used in Corpuscular Diagnostics of High Temperature Plasma to very low X-ray spectroscopy. The main purpose of this detector is to provide a state-of-the-art solution to upgrade the current detector system of the NPAs at JET and also to pave the road for the future detection systems of the ITER experimental reactor. Currently the NPAs use a very thin scintillator-photomultiplier tube [F. Garcia, S.S. Kozlovsky, D.V. Balin, Background Properties of CEM, MCP and PMT detectors at n-γ irradiation. Preprint PNPI-2392, Gatchina, 2000, p. 9 [1] ; F. Garcia, S.S. Kozlovsky, V.V. Ianovsky, Scintillation Detectors with Low Sensitivity to n-γ Background. Preprint PNPI-2391, Gatchina, 2000, p. 8 [2] ], and their main drawbacks are poor energy resolution, intrinsic scintillator nonlinearity, and relative low count rate capability and finally poor signal-to-background discrimination for the low-energy channels. The proposed new U3DTHIN detector is based on very thin sensitive substrate, which will provide nearly 100% detection efficiency for ions and at the same time very low sensitivity for neutron and gamma backgrounds. To achieve a very fast collection of the charge carriers generated by the incident ions, a 3D electrode structure [S. Parker, C. Kenney, J. Segal, Nucl. Instr. and Meth. A 395 (1997) 328 [3] ; G. Pellegrini, P. Roy, A. Al-Ajili, R. Bates, L. Haddad, M. Horn, K. Mathieson, J. Melone, V. O'Shea, K.M. Smith, Nucl. Instr. and Meth. A 487 (2002) 19 [4] ] has been introduced in the sensitive volume of the detector. The geometry of the electrode is known to be rad-hard. One of the most innovative features of these detectors is the optimal combination of the thin entrance window and the sensitive substrate thickness, which allows a very large dynamic range for ion detection. GEANT4 simulations were performed to find the losses of energy in the oxide entrance window and the energy deposition in the silicon substrate for different types of ions; results from these simulations and the process used to fabricate the U3DTHIN at the Centro Nacional de Microelectronica in Barcelona are presented.

Silicon-germanium (SiGe) heterojunction bipolar transistor (HBT) technologies promise several advantages over CMOS for the front-end readout electronics for the ATLAS upgrade. We have evaluated the relative merits of the latest generations of IBM SiGe HBT BiCMOS technologies, the 8WL and 8HP platforms. These 130 nm SiGe technologies show promise to operate at lower power than do CMOS technologies and would provide a viable alternative for the silicon strip detector and liquid argon calorimeter upgrades, provided that the radiation tolerance studies at multiple gamma and neutron irradiation levels, included in this investigation, show them to be sufficiently radiation tolerant.

A novel ultra-thin silicon detector called U3DTHIN has been designed, simulated and fabricated for applications that range from neutral particle analyzers (NPA) used in corpuscular diagnostics of High-Temperature Plasma to very low X-ray spectroscopy. The main purpose of this detector is to provide a state-of-the-art solution for the upgradation of the current detector system of the NPAs at JET and also to pave the road for the future detection systems of the ITER experimental reactor. Currently the NPAs use a very thin scintillator–photomultiplier tube, and their main drawbacks are poor energy resolution, intrinsic scintillator nonlinearity and relative low count rate capability and finally poor signal-to-background discrimination for the low energy channels. This new U3DTHIN detector is based on columnar electrodes passing through a very thin sensitive substrate, which will provide nearly 100% detection efficiency for ions and at the same time very low sensitivity for the neutron and gamma background.

Diodes fabricated on high resistivity standard, oxygenated and magnetic Czochralski p-type materials were irradiated with reactor neutrons and 24 GeV/ c protons up to an equivalent fluence of Φ eq =3×10 14 cm −2 . Radiation effects on effective trapping times, effective dopant concentration and leakage current were measured at 20 °C. Annealing of defects was performed at 20 and 60 °C.

The first results on double-sided three-dimensional (3-D) silicon radiation detectors are reported in this paper. The detector consists of a three-dimensional array of electrodes that penetrate into the detector bulk with the anode and cathode electrodes etched from opposite sides of the substrate. The geometry of the detector is such that a central anode is surrounded by four cathode contacts. The maximum drift and depletion distances are equal to the electrode spacing rather than detector thickness. This structure is similar to a conventional 3-D detector, but has a simpler fabrication process. The technological and the electrical simulations together with the fabrication steps of this new detector configuration are reported in this paper. The first detectors fabricated at CNM are reported here and have been characterized by electrical measurements.

4 pages, 5 figures.-- PACS nrs.: 29.40.−n; 29.40.Wk; 81.40.Wx.-- ISI Article Identifier: 000251861100008

We studied the radiation hardness of different SiGe BiCMOS technologies in the search for a proper microelectronic technology to be used in the design of the Front-End chip for the readout of detectors of the Inner Detector of the ATLAS Upgrade for the future Super-LHC. Gamma and neutron irradiations were performed in order to account for ionization and displacement damage. The results show that all technologies are still functional after irradiation to the levels expected at the real experiment. Small differences were observed among technologies, therefore more statistics would be needed in order to make a selection of technology for the final design.

A technology for the fabrication of p-type microstrip silicon radiation detectors using p-spray implant insulation has been developed at CNM-IMB within the RD50 collaboration framework. The p-spray insulation has been designed to withstand the ionising irradiation dose expected in the middle region of the ATLAS tracking system for the future Super-LHC. Detectors have been fabricated with Float Zone and Magnetic Czochralski p-type high resistivity silicon substrates in the Clean Room facility of CNM-IMB, irradiated with neutrons up to a fluence of 10 15 neutrons cm - 2 and characterised at IFIC-Valencia. The results show a charge collection efficiency below 40% at 1000 V bias voltage.

We have studied the ionization damage produced by gamma irradiation on transistors from three different varieties of SiGe:C HBT technologies from Innovation for High Performance Microelectronics (IHP), Germany. The results show strong gain degradations at the highest doses, with an indication of damage saturation. We did not observe strong differences in radiation tolerance among the three different technologies. These studies are in the framework of the radiation assurance tests of SiGe BiCMOS technologies for their possible application in the front-end readout electronics of the detector modules of the future ATLAS upgrade for the Super-LHC, but space-oriented applications are also considered. A comparison is presented with previous gamma irradiations of different SiGe technologies in the literature.

This paper presents a high-density bumping technique based on electrodeposition of the bump materials. The idea of such technique is to allow the packaging of densely populated chips such as array pixel detectors. Silicon pixel detector dummies have been designed and fabricated at CNM in order to evaluate the technique developed. Special test structures have been included in these dummies to evaluate the final yield of the process developed at CNM. The foreseen applications are Medical Imaging and X-ray systems. The new bumping technique developed will greatly improve the simplicity and the cost of the packaging process.

In photon-counting imaging devices, charge sharing can limit the detector spatial resolution and contrast, as multiple counts can be induced in adjacent pixels as a result of the spread of the charge cloud generated from a single X-ray photon of high energy in the detector bulk. Although debated for a long time, the full impact of charge sharing has not been completely assessed. In this work, the importance of charge sharing in pixellated CdTe and silicon detectors is studied by exposing imaging devices to different low activity sources. These devices are made of Si and CdTe pixel detector bump-bonded to Medipix2 single-photon-counting chips with a 55 μm pixel pitch. We will show how charge sharing affects the spatial detector resolution depending on incident particle type (alpha, beta and gamma), detector bias voltage and read-out chip threshold. This study will give an insight on the impact on the design and operation of pixel detectors coupled to photon-counting devices for imaging applications.

This work reports on an optimization study of the p-spray profile for the fabrication of n-in-p microstrip silicon detectors. A thorough simulation process of the expected electrical performance of different p-spray technologies was carried out. The best technological options for the p-spray implantation were chosen for the fabrication of miniature n-in-p microstrip detectors on high resistivity FZ wafers at the IMB-CNM clean room. The main conclusions derived from the simulations, and the electrical performance of a sample of the fabricated devices is presented.

A further development of a new technological solution to improve the beam-loss protection of silicon strip sensors used in large High Energy Physics experiments is presented. Previous studies show that the high strip resistance limits the beneficial effect of full Punch-Through protection (PTP) structures to the area near the structures. In our approach, we extended the PTP protection to the full active area of the sensor by lowering the strip resistance. This is achieved by the addition of a low-resistivity layer connected along the whole strip implant. We have previously demonstrated that such sensors performed as expected, and that other sensor performance factors are not compromised due to the technological modification. The current studies are focused on two aspects of practical application: manufacturability of the sensors with high yield, and their radiation tolerance. To that extend we have made devices with alternative methods of making low-resistivity layers that with better technological performance, and we have irradiated them with protons in the range expected for upgraded ATLAS strips system. The results show that the sensors fabricated with these alternative technological methods remain within specs and that the strip resistance is properly reduced. On the other hand, radiation does not affect the reduced strip resistance.