Design and standalone characterisation of a capacitively coupled HV-CMOS sensor chip for the CLIC vertex detector

The concept of capacitive coupling between sensors and readout chips is under study for the vertex detector at the proposed high-energy CLIC electron positron collider. The CLICpix Capacitively Coupled Pixel Detector (C3PD) is an active High-Voltage CMOS sensor, designed to be capacitively coupled to the CLICpix2 readout chip. The chip is implemented in a commercial $180$ nm HV-CMOS process and contains a matrix of $128\times128$ square pixels with $25$ $\mu$m pitch. First prototypes have been produced with a standard resistivity of $\sim20$ $\Omega$cm for the substrate and tested in standalone mode. The results show a rise time of $\sim20$ ns, charge gain of $190$ mV/ke$^{-}$ and $\sim40$ e$^{-}$ RMS noise for a power consumption of $4.8$ $\mu$W/pixel. The main design aspects, as well as standalone measurement results, are presented.Comment: 13 pages, 13 figures, 2 tables. Work carried out in the framework of the CLICdp collaboratio

Etude et caractérisation d'un capteur en silicium amorphe hydrogéné déposé sur circuit intégré pour la détection de particules et de rayonnements

Next generation experiments at the European laboratory of particle physics (CERN) require particle detector alternatives to actual silicon detectors. This thesis presents a novel detector technology, which is based on the deposition of a hydrogenated amorphous silicon sensor on top of an integrated circuit. Performance and limitations of this technology have been assessed for the first time in this thesis in the context of particle detectors. Specific integrated circuits have been designed and the detector segmentation, the interface sensor â chip and the sensor leakage current have been studied in details. The signal induced by the track of an ionizing particle in the sensor has been characterized and results on the signal speed, amplitude and on the sensor resistance to radiation are presented. The results are promising regarding the use of this novel technology for radiation detection, though limitations have been shown for particle physics application

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

A 64-channel, 1.1-pA-accurate on-chip potentiostat for parallel electrochemical monitoring

Electrochemical monitoring is crucial for both industrial applications, such as microbial electrolysis and corrosion monitoring as well as consumer applications such as personal health monitoring. Yet, state-of-the-art integrated potentiostat monitoring devices have few parallel channels with limited flexibility due to their channel architecture. This work presents a novel, widely scalable channel architecture using a switch capacitor based Howland current pump and a digital potential controller. An integrated, 64-channel CMOS potentiostat array has been fabricated. Each individual channel has a dynamic current range of 120dB with 1.1pA precision with up to 100kHz bandwidth. The on-chip working electrodes are post-processed with gold to ensure (bio)electrochemical compatibility

An Energy-Efficient, Dynamic Voltage Scaling Neural Stimulator for a Proprioceptive Prosthesis

Accepted versio

Fabrication of single walled carbon nanotube (SW-CNT) cantilevers for chemical sensing

With the discovery of carbon nanotubes (CNTs), many applications have been implemented based on their unique electronic, mechanical, chemical and optoelectronic properties. One area of applications is in gas sensors for detecting, oxygen, flammable and toxic gases. In our work, the focus is on the fabrication of carbon nanotube (CNT) cantilever sensors for integration with CMOS readout chip which offer increased sensitivity. The higher surface-to-bulk ratio enhances the property and performance of the gas sensor by nanocantilevers. In this work, we present the detection method based on the change in capacitance of the single walled carbon nanotube (SWCNT) cantilever. Carbon nanotubes are capable of interacting with the gaseous species either directly or indirectly by using a polymer analyte coated on its surface. The capacitance variation technique of measuring cantilever deflection was used to measure the bending rate. The capacitance between the cantilever and the fixed electrode varies as a function of the magnitude of the bending of the cantilever which is in turn proportional to the concentration of the gas species in the surrounding environment. To measure the variation in the capacitance value, the CNT cantilever beam is considered as one of the electrodes of the capacitor and the metal film as the other. The air between the plates acts as the dielectric material. Simulations including both ANSYS for nanocantilevers and SPICE for CMOS readout chip and experimental results are presented in this research. Integration and packaging issues are also discussed in our research