Impact of Dark Current on Pinned Photo-Diode Capacitance of CMOS Image Sensor in Low illumination Regime

Abstract

Abstract Low-light imaging is an essential characteristic of Space and Quanta sensing applications. For an accurate design and optimization of image sensor pixels, the analysis of Dark Current generation mechanisms including effects of Temperature, Trap concentration and Trap Cross-section is essential. TCAD optoelectrical simulations are used to calculate the thresholds of the above generation effects and the corresponding Dynamic Pinned Photo-Diode (PPD) capacitance variations. An interfacial Trap model with various generation models activated allows comparison of variations in PPD capacitance on a widely used PPD model both in light and dark. This allows the remodeling of existing CMOS image sensor compact models to capture the Dark Current effects in a Low illumination regime. The compact model shows a deviation of 6.85% from the physical device.