Implementation and Characterisation of Monolithic CMOS Pixel Sensors for the CLIC Vertex and Tracking Detectors

Different CMOS technologies are being considered for the vertex and tracking layers of the detector at the proposed high-energy e$^{+}$e$^{−}$ Compact Linear Collider (CLIC). CMOS processes have been proven to be suitable for building high granularity, large area detector systems with low material budget and low power consumption. An effort is put on implementing detectors capable of performing precise timing measurements. Two Application-Specific Integrated Circuits (ASICs) for particle detection have been developed in the framework of this thesis, following the specifications of the CLIC vertex and tracking detectors. The process choice was based on a study of the features of each of the different available technologies and an evaluation of their suitability for each application. The CLICpix Capacitively Coupled Pixel Detector (C3PD) is a pixelated detector chip designed to be used in capacitively coupled assemblies with the CLICpix2 readout chip, in the framework of the vertex detector at CLIC. The chip comprises a matrix of 128×128 square pixels with 25 µm pitch. A commercial 180 nm High-Voltage (HV) CMOS process was used for the C3PD design. The charge is collected with a large deep N-well, while each pixel includes a preamplifier placed on top of the collecting electrode. The C3PD chip was produced on wafers with different values for the substrate resistivity (∼ 20, 80, 200 and 1000 Ωcm) and has been extensively tested through laboratory measurements and beam tests. The design details and characterisation results of the C3PD chip will be presented. The CLIC Tracker Detector (CLICTD) is a novel monolithic detector chip developed in the context of the silicon tracker at CLIC. The CLICTD chip combines high density, mixed mode circuits on the same substrate, while it performs a fast time-tagging measurement with 10 ns time bins. The chip is produced in a 180 nm CMOS imaging process with a High-Resistivity (HR) epitaxial layer. A matrix of 16×128 detecting cells, each measuring 300 × 30 µm$^{2}$ , is included. A small N-well is used to collect the charge generated in the sensor volume, while an additional deep N-type implant is used to fully deplete the epitaxial layer. Using a process split, additional wafers are produced with a segmented deep N-type implant, a modification that has been simulated to result in a faster charge collection time. Each detecting cell is segmented into eight front-ends to ensure prompt charge collection in the sensor diodes. A simultaneous 8-bit timing and 5-bit energy measurement is performed in each detecting cell. A detailed description of the CLICTD design will be given, followed by the first measurement results

Transient Monte Carlo Simulations for the Optimisation and Characterisation of Monolithic Silicon Sensors

An ever-increasing demand for high-performance silicon sensors requires complex sensor designs that are challenging to simulate and model. The combination of electrostatic finite element simulations with a transient Monte Carlo approach provides simultaneous access to precise sensor modelling and high statistics. The high simulation statistics enable the inclusion of Landau fluctuations and production of secondary particles, which offers a realistic simulation scenario. The transient simulation approach is an important tool to achieve an accurate time-resolved description of the sensor, which is crucial in the face of novel detector prototypes with increasingly precise timing capabilities. The simulated time resolution as a function of operating parameters as well as the full transient pulse can be monitored and assessed, which offers a new perspective on the optimisation and characterisation of silicon sensors. In this paper, a combination of electrostatic finite-element simulations using 3D TCAD and transient Monte Carlo simulations with the Allpix Squared framework are presented for a monolithic CMOS pixel sensor with a small collection diode, that is characterised by a highly inhomogeneous, complex electric field. The results are compared to transient 3D TCAD simulations that offer a precise simulation of the transient behaviour but long computation times. Additionally, the simulations are benchmarked against test-beam data and good agreement is found for the performance parameters over a wide range of different operation conditions

Optimization of a 65 nm CMOS imaging process for monolithic CMOS sensors for high energy physics

The long term goal of the CERN Experimental Physics Department R&D on monolithic sensors is the development of sub-100nm CMOS sensors for high energy physics. The first technology selected is the TPSCo 65nm CMOS imaging technology. A first submission MLR1 included several small test chips with sensor and circuit prototypes and transistor test structures. One of the main questions to be addressed was how to optimize the sensor in the presence of significant in-pixel circuitry. In this paper this optimization is described as well as the experimental results from the MLR1 run confirming its effectiveness. A second submission investigating wafer-scale stitching has just been completed. This work has been carried out in strong synergy with the ITS3 upgrade of the ALICE experiment

Characterisation of capacitively coupled HV/HR-CMOS sensor chips for the CLIC vertex detector

The capacitive coupling between an active sensor and a readout ASIC has been considered in the framework of the CLIC vertex detector study. The CLICpix Capacitively Coupled Pixel Detector (C3PD) is a High-Voltage CMOS sensor chip produced in a commercial 180 nm HV-CMOS process for this purpose. The sensor was designed to be connected to the CLICpix2 readout chip. It therefore matches the dimensions of the readout chip, featuring a matrix of 128 × 128 square pixels with 25 μm pitch. The sensor chip has been produced with the standard value for the substrate resistivity (∼ 20 Ωcm) and it has been characterised in standalone testing mode, before receiving and testing capacitively coupled assemblies. The standalone measurement results show a rise time of ∼ 20 ns for a power consumption of 5 μW/pixel. Production of the C3PD HV-CMOS sensor chip with higher substrate resistivity wafers (∼ 20, 80, 200 and 1000 Ωcm) is foreseen. The expected benefits of the higher substrate resistivity will be studied using future assemblies with the readout chip

Design of a monolithic HR-CMOS sensor chip for the CLIC silicon tracker

The CLIC Tracker Detector (CLICTD) is a monolithic active pixel sensor targeted at the tracking detector of a future experiment at the Compact Linear Collider (CLIC). The chip features a matrix of $16 \times 128$ cells, each cell measuring $300 \times 30\,\mu m^{2}$ . The cells are segmented in the long direction in order to maintain the benefits of the small collection electrode. In the digital logic, a simultaneous 8-bit Time of Arrival and 5-bit Time over Threshold measurement is performed. A 180 nm HR-CMOS Imaging Process was selected for the design of a chip that will meet the requirements of the tracker at CLIC. In this document, the CLICTD design and chip interface are presented

CLICTD: A monolithic HR-CMOS sensor chip for the CLIC silicon tracker

The CLIC Tracker Detector (CLICTD) is a monolithic pixelated sensor chip produced in a 180 nm imaging CMOS process with a high-resistivity epitaxial layer. The chip, designed in the context of the CLIC tracking detector study, comprises a matrix of 16 × 128 detector channels, each measuring 300 × 30 μm$^2$ . To ensure prompt charge collection, every channel is segmented in eight collection diodes, each containing a separate analog front-end. A simultaneous 8-bit time and 5-bit energy measurement is performed in the on-channel digital logic. The main design aspects as well as the first results from laboratory measurements with the CLICTD are presented

Corryvreckan: A Modular 4D Track Reconstruction and Analysis Software for Test Beam Data

Corryvreckan is a versatile, highly configurable software with a modular structure designed to reconstruct and analyse test beam and laboratory data. It caters to the needs of the test beam community by providing a flexible offline event building facility to combine detectors with different read-out schemes, with or without trigger information, and includes the possibility to correlate data from multiple devices based on timestamps. Hit timing information, available with high precision from an increasing number of detectors, can be used in clustering and tracking to reduce combinatorics. Several algorithms, including an implementation of Millepede-II, are provided for offline alignment. A graphical user interface enables direct monitoring of the reconstruction progress and can be employed for quasi-online monitoring during data taking. This work introduces the Corryvreckan framework architecture and user interface, and provides a detailed overview of the event building algorithm. The reconstruction and analysis capabilities are demonstrated with data recorded at the DESY II Test Beam Facility using the EUDAQ2 data acquisition framework with an EUDET-type beam telescope, a Timepix3 timing reference, a fine-pitch planar silicon sensor with CLICpix2 readout and the AIDA Trigger Logic Unit. The individual steps of the reconstruction chain are presented in detail

Corryvreckan: A Modular 4D Track Reconstruction and Analysis Software for Test Beam Data

Corryvreckan is a versatile, highly configurable software with a modular structure designed to reconstruct and analyse test beam and laboratory data. It caters to the needs of the test beam community by providing a flexible offline event building facility to combine detectors with different read-out schemes, with or without trigger information, and includes the possibility to correlate data from multiple devices based on timestamps. Hit timing information, available with high precision from an increasing number of detectors, can be used in clustering and tracking to reduce combinatorics. Several algorithms, including an implementation of Millepede-II, are provided for offline alignment. A graphical user interface enables direct monitoring of the reconstruction progress and can be employed for quasi-online monitoring during data taking. This work introduces the Corryvreckan framework architecture and user interface, and provides a detailed overview of the event building algorithm. The reconstruction and ana- lysis capabilities are demonstrated with data recorded at the DESY II Test Beam Facility using the EUDAQ2 data acquisition framework with an EUDET-type beam telescope, a Timepix3 timing reference, a fine-pitch planar silicon sensor with CLICpix2 readout and the AIDA Trigger Logic Unit. The individual steps of the reconstruction chain are presented in detail.Corryvreckan is a versatile, highly configurable software with a modular structure designed to reconstruct and analyse test beam and laboratory data. It caters to the needs of the test beam community by providing a flexible offline event building facility to combine detectors with different read-out schemes, with or without trigger information, and includes the possibility to correlate data from multiple devices based on timestamps. Hit timing information, available with high precision from an increasing number of detectors, can be used in clustering and tracking to reduce combinatorics. Several algorithms, including an implementation of Millepede-II, are provided for offline alignment. A graphical user interface enables direct monitoring of the reconstruction progress and can be employed for quasi-online monitoring during data taking. This work introduces the Corryvreckan framework architecture and user interface, and provides a detailed overview of the event building algorithm. The reconstruction and analysis capabilities are demonstrated with data recorded at the DESY II Test Beam Facility using the EUDAQ2 data acquisition framework with an EUDET-type beam telescope, a Timepix3 timing reference, a fine-pitch planar silicon sensor with CLICpix2 readout and the AIDA Trigger Logic Unit. The individual steps of the reconstruction chain are presented in detail.Corryvreckan is a versatile, highly configurable software with a modular structure designed to reconstruct and analyse test beam and laboratory data. It caters to the needs of the test beam community by providing a flexible offline event building facility to combine detectors with different readout schemes, with or without trigger information, and includes the possibility to correlate data from multiple devices based on timestamps. Hit timing information, available with high precision from an increasing number of detectors, can be used in clustering and tracking to reduce combinatorics. Several algorithms, including an implementation of Millepede-II, are provided for offline alignment. A graphical user interface enables direct monitoring of the reconstruction progress and can be employed for quasi-online monitoring during data taking. This work introduces the Corryvreckan framework architecture and user interface, and provides a detailed overview of the event building algorithm. The reconstruction and analysis capabilities are demonstrated with data recorded at the DESY II Test Beam Facility using the EUDAQ2 data acquisition framework with an EUDET-type beam telescope, a Timepix3 timing reference, a fine-pitch planar silicon sensor with CLICpix2 readout and the AIDA Trigger Logic Unit. The individual steps of the reconstruction chain are presented in detail

Comparison of different sensor thicknesses and substrate materials for themonolithic small collection-electrode technology demonstrator CLICTD

Small collection-electrode monolithic CMOS sensors profit from a high signal-to-noise ratio and a small power consumption, but have a limited active sensor volume due to the fabrication process based on thin high-resistivity epitaxial layers. In this paper, the active sensor depth is investigated in the monolithic small collection-electrode technology demonstrator CLICTD. Charged particle beams are used to study the charge-collection properties and the performance of devices with different thicknesses both for perpendicular and inclined particle incidence. In CMOS sensors with a high-resistivity Czochralski substrate, the depth of the sensitive volume is found to increase by a factor two in comparison with standard epitaxial material and leads to significant improvements in the hit-detection efficiency and the spatial and time resolution