Enhancement of PDE and Noise Characteristics by Trench Guide with 2x2 Small Lens Array and Backside Pixel Isolation for 7μm SPAD Pixel

We present an optimized Light Detection and Ranging (LiDAR) process for 7 mu m Single Photon Avalanche Diode (SPAD) pixel. We achieved a Photon Detection Efficiency (PDE) more than two times higher by using a Trench Guide (TG) and a 2x2 Small Lens Array (SLA) as optical structures. Additionally, we physically divided the pixels using Backside Pixel Isolation (BPI), which reduced both electrical and optical crosstalk, improving the noise characteristics of the SPAD sensor. Finally, we achieved a PDE of 26.4% at lambda =940 nm,Vex=2.5 V, and an error rate of less than 0.4% in the average depth accuracy performance of the SPAD sensor