Influencing factors of noise characteristics in EBCMOS with uniformly doped P-type substrates

Abstract In this study, with the aim of achieving a high signal-to-noise ratio (SNR) in an electron-bombarded complementary metal−oxide−semiconductor (EBCMOS) imaging chip, we analyzed the sources of noise using principles from low-light-level imaging and semiconductor theory, and established a physical computational model that relates the electron-multiplication layer to the noise characteristics of an EBCMOS chip in a uniformly doped structure with a P-type substrate. We conducted theoretical calculations to analyze the effects on noise characteristics of the passivation layer material and thickness, P-substrate doping concentration, P-substrate thickness, incident electron energy, and substrate temperature. By comparing the characteristics of pixel noise, dark current, multiplication electron numbers, and SNR under various structures, we simulated optimized structural parameters of the device. Our simulation results showed that the noise characteristics of the device could be optimized using an Al 2 O 3 passivation thickness of 15 nm and substrate temperature of 260 K, and by decreasing the doping concentration and thickness of the P-type substrate and increasing the incident electron energy. The optimized SNR were 252 e/e. And the substantial impact of dark current noise, primarily governed by interfacial defects, on the overall noise characteristics of the device. This research offers theoretical support to develop EBCMOS imaging chips with high gain and SNR.