Backside passivation for improving the noise performance in CMOS image sensor

Great efforts have been made in the past few years to reduce the white pixel noise in complementary metal-oxide-semiconductor (CMOS) image sensors. As a promising approach, the surface passivation method focusing on the field-effect passivation has been studied in this work. Based on the metal-oxide-semiconductor capacitor device model, electrical measurement and analysis have been performed for characterizing the charge distribution in the system. The relationship between the flat band voltage and the white pixel performance has been set up, and the proposed passivation method that controls Si or SiO2 interface charge or traps has been proved effective in lowering the white pixel noise, which can be very attractive in improving the performance of CMOS image sensors for high-resolution and high-sensitivity applications.