The role of ionization coefficient in the operation of avalanche diodes above breakdown

Abstract

The behavior of the avalanche triggering probability in pn junction diodes biased above breakdown is a sensitive function of the form of the field dependence of αe and αh. In this paper we present theoretical predictions of electron and hole initiated avalanche triggering probabilities in planar, cylindrical, and spherical junctions. These probabilities are calculated as a function of excess bias above breakdown for various forms of αe and αh versus E. We also show recent experimental data for electron and hole triggering in planar diodes. The absolute electron triggering probability is measured to an accuracy of about ± 40%. The form of the electron and hole triggering probabilities versus bias are more accurately determined. Both the absolute and relative triggering probabilities are in good agreement with the theoretical prediction based on αe and αh forms of either Grant or Van Overstraeten and De Man.