Model of single-electron performance of micropixel avalanche photodiodes

TL;DR

This paper presents an approximate iterative model for the avalanche process in micropixel avalanche photodiodes initiated by a single photoelectron, incorporating electric field changes and comparing results with experimental data.

Contribution

It introduces a novel iterative model that describes avalanche development over time, accounting for internal and external currents, and provides insights into pulse characteristics and pixel capacitance.

Findings

Discharge current edges last less than 50 ps.

External recharge current edge duration depends on quenching resistor.

Effective pixel capacitance is twice the real capacitance.

Abstract

An approximate iterative model of avalanche process in a pixel of micropixel avalanche photodiode initiated by a single photoelectron is presented. The model describes development of the avalanche process in time, taking into account change of electric field within the depleted region caused by internal discharge and external recharge currents. Conclusions obtained as a result of modelling are compared with experimental data. Simulations show that typical durations of the front and rear edges of the discharge current have the same magnitude of less than 50 ps. The front of the external recharge current has the same duration, however duration of the rear edge depends on value of the quenching micro-resistor. It was found that effective capacitance of the pixel calculated as the slope of linear dependence of the pulse charge on bias voltage exceeds its real capacitance by a factor of two, while the total pixel voltage drop equals twice the value of bias overvoltage.