Design of Transfer-Gated CMOS Active Pixels Deploying Conventional PN-Junction Photodiodes

Abstract

This paper presents a comparative study of six active pixel sensor (APS) schemes by means of simulations and experiments. The optical sensor used was a silicon photodiode with integrated electronics in a standard 0.35 µm CMOS technology. We analyzed how the transistor characteristics, such as channel resistance and leakage current, among others, can influence the APS response. Furthermore, we demonstrated how the choice of APS model affects sensor parameters such as output swing and fill factor, among others. The results presented and the understanding of the operational cycle of the CMOS transfer-gated APS aims at guiding better choices for different applications and the better transistor type in the project.