Comprehensive Modeling of Photon Detection Probability in CMOS-based SPADs

Due to high sensitivity and CMOS compatibility, the single-photon avalanche diode (SPAD) is a promising optical detector in many applications. The sensitivity of a SPAD described by photon detection probability is a key parameter to be investigated. This paper presents a comprehensive model to characterize the photon detection probability of CMOS-implemented SPADs in technologies where an anti-reflection coating layer is not available. The model can accurately capture optical, photon absorption, and avalanche triggering effects. The obtained simulation results show a good agreement to our experimental evaluations and, therefore, the model can be reliably used to characterize the detection efficiency of CMOS SPADs for accurate device simulation and optimization.