Verilog-A model for avalanche dynamics and quenching in Single-Photon Avalanche Diodes

We present a Verilog-A model accounting for the temporal avalanche buildup and its statistics in Single-Photon Avalanche Diodes (SPADs). This physics-based approach is compared to TCAD mixed-mode analyzing predictions, as well as measurements. The buildup that can be in the order of hundreds picoseconds, affects the statistical pulse width distribution, which is experimentally verified. Furthermore, we address in detail the voltage swing across the device during avalanche and its quenching, studying its impact on power consumption. This model can help a chip designer to optimize circuits for quenching the SPAD photodiode.