A 640×480 Indirect Time-of-Flight CMOS Image Sensor with 4-tap 7-μm Global-Shutter Pixel and Fixed-Pattern Phase Noise Self-Compensation Scheme

Min-Sun Keel, Young-Gu Jin, Youngchan Kim, Daeyun Kim, Yeomyung Kim, Myunghan Bae, Bumsik Chung, Sooho Son, Hogyun Kim, Taemin An, Sung-Ho Choi, Taesub Jung, Yonghun Kwon, Sungyoung Seo, Sae-Young Kim, Kwanghyuk Bae, Seung-Chul Shin, Myoungoh Ki, Chang-Rok Moon, Hyunsurk Ryu

Abstract: A 640 × 480 indirect Time-of-Flight (ToF) CMOS image sensor has been designed with 4-tap 7-μm global-shutter pixel in 65-nm back-side illumination (BSI) process. With novel 4-tap pixel structure, we achieved motion artifact-free depth map. Column fixed-pattern phase noise (FPPN) is reduced by introducing alternative control of the clock delay propagation path in the photo-gate driver. As a result, motion artifact and column FPPN are not noticeable in the depth map. The proposed ToF sensor shows depth noise less than 0.62% with 940-nm illuminator over the working distance up to 400 cm, and consumes 197 mW for VGA, which is 0.64 pW/pixel.