Modeling and simulation of SPAD quenching including space-charge effect

Abstract We present a transient, self-consistent single-photon avalanche diodes (SPAD) model that couples an advection-diffusion Monte Carlo transport solver to a finite-element Poisson solver and a passive quench circuit. The method stochastically treats impact ionization via a random-path-length algorithm and captures the avalanche-induced space-charge effect that impacts quenching. Statistical analyses reveal the influence of stochastic fluctuations and device geometry on avalanche and quenching dynamics. We demonstrate the importance of space-charge effect effects in the quenching process and show that our method can simulate micron-scale SPAD devices with nanosecond RC time constants, yielding results consistent with experimental data.