A new physical model of Geiger-mode avalanche photodiodes

A new physical model of avalanche process with single photon detection capabilities is presented. The model describes the avalanche process, taking into account the resistance of space charge, parasitic capacitance as well as the changes of electric field during avalanche process caused by internal discharge and external recharge currents. The results of simulation are compared with the experimental data obtained with photodiodes from different manufacturers. It was determined that at a fixed value of overvoltage, the signal gain decreases significantly, depending on the resistance of the space charge region. This paper presents also the possibilities for improving the parameters of silicon photomultipliers.