A 336 x 240 Backside-Illuminated 3D-Stacked 7μm SPAD for LiDAR Sensor with PDE 28% at 940nm and under 0.4% Depth Accuracy Up to 10m

Jaehyung Jang, Jongchae Kim, Sunho Oh, Kyungsu Byun, Dahwan Park, Jihee Han, Hanseung Lee, Suhyun Yi, Hoonmoo Choi, Jongeun Kim, Namil Kim, Yongtae Gim, Minkyu Kim, Sangyoung Lee, Hansang Kim, Eunchang Lee, Minsang Yu, Jeongjoon Hwang, Seunghyun Yoon, Kwang Hwangbo et al. (10 additional authors not shown)

Abstract: Single photon avalanche diode (SPAD) is a key technology in light detection and ranging (LiDAR) sensors, which are gaining prominence as next-generation image sensors. We designed SPAD with high photon detection efficiency (PDE) using a backside-illuminated hybrid bonding 3D-stacked technology. This is aimed at developing a LiDAR sensor with good depth accuracy. We achieved a PDE of 28% at $\lambda= 940\text{nm}$ and a low-level dark count rate (DCR) by applying the trench guide (TG) and the small lens array (SLA) structure and optimizing pixel design. As a result, we achieved a depth accuracy of less than 0.4% up to 10m.