A Two-Tap Indirect Time-of-Flight CMOS Image Sensor With Pump Gate Modulator for Low-Power Applications

A 320 $\times $ 240 indirect time-of-flight (i-ToF) image sensor with a 5.6- $\mu \text{m}$ two-tap 1.5-V pump gate modulation pixel has been designed. Novel characteristics, such as the optimized pinned layer doping and potential buffer region (PBR) structure with pump gate modulator (PGM), are proposed to achieve a maximum lateral modulation electric field of 1500 V/cm under the front-side illumination (FSI) process. As a result, the proposed time-of-flight (ToF) sensor shows 200-mW power consumption and 54% demodulation contrast (DC) at 50-MHz modulation frequency, depth noise less than 1% with 940-nm illuminator from 0.3 to 3 m.