Influence of tunneling processes on avalanche breakdown in Ge and Si

Abstract

The microplasma pulse rate of Ge and Si avalanche diodes has been investigated in the temperature range 30–300 K. It is shown that minority carriers which trigger the avalanche are created by tunneling at low temperatures. In Ge the turn‐on probability of avalanche pulses can be explained by direct gap tunneling; contributions of indirect gap tunneling are small. At high temperature, thermal generation of minority carriers contributes to the turn‐on probability. In Si on the other hand, (indirect gap) tunneling contributions are small and thermal generation determines the turn‐on probability over the entire temperature range observed.