Analysis and Validation of High-Accuracy Simple Monte Carlo Model for Photon Detection Probability in SPAD

Silicon-based single-photon avalanche diodes (SPADs) can realize extremely weak light detection, and are widely used in marine LiDAR, space exploration, fluorescence imaging and other fields. Accurately modeling the photon detection probability (PDP) of SPAD is crucial for promoting the performance of photoelectric sensors. In this paper, the SPADs are used to simulate the microscopic motion process of carriers based on the simple Monte Carlo (SMC) model, which in turn predicts the macroscopic electrical parameter PDP. Utilizing the SMC model, we designed and fabricated two types of SPAD devices with different avalanche junctions using the 0.18 μm Bipolar-CMOS-DMOS (BCD) process. The experimental test results closely match our predictions: for SPAD-A (N+/PW avalanche junction), the absolute average error for PDP is 1.48%, with the maximum error of 5.20%@360 nm. For SPAD-B (P+/NW avalanche junction), the absolute average error for PDP is 1.61%, with a maximum error of 5.10%@900 nm.