Zener and avalanche breakdown in silicon alloyed p- n junctions—II : Effect of temperature on the reverse characteristics and criteria for distinguishing between the two breakdown mechanisms

Abstract

The effect of temperature on the reverse current and breakdown voltage of silicon p- n junctions for a wide range of breakdown voltages has been investigated and the criteria for differentiating the Zener breakdown from avalanche breakdown have been presented. Narrow p- n junctions with soft characteristics have a temperature insensitive reverse current, contributed by internal field emission and show a negative temperature coefficient β of breakdown voltage which is determined up to large extent by the available phonon density present in tunnelling transitions. Wider junctions with V B > 13 V show a highly temperature sensitive current and a positive value of β, which is in good agreement with the avalanche multiplication theory. For values of V B from 3.5 to 13 V there is a transition region from Zener to avalanche type of breakdown in which the temperature dependence of the reverse characteristics is complex and cannot be accounted by a single mechanism. Apart from the temperature dependence of breakdown voltage such properties as generation of microplasma noise, dependence of breakdown voltage on impurity concentration, space-charge layer width and maximum field strength at breakdown have been found to show distinct differences between Zener and avalanche regions and give a further support to the conclusions reached from the temperature studies.