Radiation-induced phenomena constitute a big concern for image sensors dedicated to space application. Particles (such as protons or electrons) can impact the crystalline structure of the detector and create switches in the dark response. This may be a problem, especially for calibration and so on image quality. This article aims at expressing the method used for switch detection and showing some properties of these Random Telegraph Signals (RTS), concerning, among other things, their amplitudes, discrete levels, and switching times. A first analysis of these results is also given.

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In this work, several studies on Total Ionizing Dose effects on Pinned Photodiode CMOS images sensors are presented. More precisely, the evolution of a parasitic signal called Random Telegraph Signal is analysed through several photodiode designs. It is shown that the population of pixels exhibiting this fluctuation depends on the design variants. This population also increases in a different way with the dose: the effects are not same considering a low or high X-rays irradiation. Moreover, a statistical analysis is realized in order to better caracterize the defects responsible for RTS. It turns out that electric field enhancement signature can appear in some specific cases.

This paper investigates the leakage currents as well as the leakage current Random Telegraph Signals (RTSs) sources in sense node floating diffusions (FDs) and their consequences on imaging performances specifically after exposure to high-energy particle radiation. Atomic displacement damage and ionization effects are separately studied thanks to neutron and X-ray irradiations. Proton irradiations have been performed to simultaneously study displacement damage dose (DDD) and total ionizing dose (TID) effects while being more representative of the space environment. The studied DDD ranges from 500 TeV • g −1 to 40 GeV • g −1 , and the TID ranges from 24 krad(SiO 2) to 72 krad(SiO 2). High-magnitude electric field effects, such as transfer-gate-induced leakage current, are investigated to further understand the phenomena involved in FDs while giving new insights into the Electric Field Enhancement of the charge generation mechanisms. This paper shows that FDs are very sensitive to ionizing radiation because of the presence of depleted Si/SiO 2 interface with high-magnitude electric fields around the junction. On the other hand, displacement damage in the FDs is a major source of high amplitude leakage current RTSs and leakage current nonuniformity. Such radiation-induced degradations can prevent the use of CMOS image sensor with long FD retention time (e.g., global shutter operating mode or burst imagers) in radiation environments.