Dr. Martin Prest: Martin received his PhD from the University of Warwick in 2001 where he studied SiGe MOSFETs, germanium was used to strain the lattice in thin SiGe alloy layers; the layers formed quantum wells in the device with high carrier mobility. He studied carrier mobility at low-temperature and fitted carrier scattering models to measurements. The valence-band offset in SiGe pMOS was shown to reduce 1/f noise. His post-doctoral research at Warwick involved investigation of strained-silicon MOSFETs and Schottky source-drain contacts. He also used tunnel junctions between strained-silicon and superconducting aluminium for electron-cooling below 300 mK and for applications in THz sensors and imaging. At Birmingham University he developed and demonstrated a micro-mechanical actuator for tuning of a superconducting microwave resonator with operation at 77 K. At Cardiff University he developed finite-element models of thermoelectric power convertors, optimising geometry for integration with solar-cells. Since joining CEI in June 2018 Martin has been using Silvaco simulation tools for the development of image sensors.
Development of semiconductor image sensors for space applications. Simulation of CMOS and CCD image sensors to optimise charge collection efficiency.
|Role||Start date||End date||Funding source|
|Lead||01 Apr 2021||31 Dec 2022||ESA (European Space Agency)|
We propose to manufacture CMOS image sensors with a novel nanostructured black silicon (b-Si) anti-reflection (AR) coating and to characterize their electro-optical performance. Initial results from tests of this coating, developed by Aalto University (Finland), show that it can increase the quantum efficiency (QE) of silicon detectors to nearly 100% throughout the visible and NIR wavelengths, and even exceed 100% QE below 300 nm. For CMOS image sensors the nearly flat QE would be a breakthrough development, considering that traditional AR coatings are optimised only for a specific wavelength band. The study is needed to establish whether the b-Si process, presently used only on large area p+/n photodiodes, can be applied to established commercial backside-illuminated (BSI) CMOS image sensors using p-type epitaxial substrate, manufactured by our industrial partner Teledyne e2v. We plan to characterise the QE over the wavelength range 400-1000 nm and to establish whether the b-Si coating deteriorates the uniformity of the photoresponse and the dark current of the sensors. If successful, this project will represent a major advance in AR technology for pixelated sensors and would substantially improve the performance of future silicon detectors for space and other applications.
Pinned Photodiode Imaging Pixel With Floating Gate Readout and Dual Gain (2023)
Stefanov, Konstantin D. and Prest, Martin J.
IEEE Transactions on Electron Devices, 70(6) (pp. 3136-3139)
Simulations and Design of a Single-Photon CMOS Imaging Pixel Using Multiple Non-Destructive Signal Sampling (2020)
Stefanov, Konstantin; Prest, Martin J.; Downing, Mark; George, Elizabeth; Bezawada, Naidu and Holland, Andrew