Study of a Single-Photon Avalanche Diode Models

In this paper, we present a study of circuit models for single-photon avalanche diodes (SPADs). We used Orcad PSpice software to model the device and to represent the detector's behavior in Geiger mode. This model properly characterizes the self-sustaining avalanche and the self-quenching process. Through this model, we were able to correctly present the avalanche current signal, the voltage drop and the recovery time in the SPAD's cathode. The results obtained with such a model show a good corresponding with experimental measurements acquired with passive quenching circuit (PQC). Such a study allows us to present better results for the avalanche process and enable us to detect weak avalanches.