An experimental investigation on the nature of reverse current of silicon power pn-junctions

At this time, little importance is given to the surface component of reverse leakage current of silicon pn-junctions although reliability issues reveal device blocking weakness when performing at high voltage and temperature. Junctions which have almost the same perimeter but different area have been realized and their reverse current has been measured at room temperature and high temperature both for standard recovery and fast recovery (gold-doped or electron irradiated) pn-junctions. It is shown that for standard recovery junctions the surface component of the reverse current is the primary component from room temperature up to above 150°C and has influence on reaching high permissible working voltages. For gold-doped or electron irradiated junctions, the bulk component is dominant at high junction temperature, but it is shown that a comparatively negligible surface component can impose lower reverse working voltages or lower junction operation temperature. The surface component may be a cause of limitation on the operation of power silicon diodes at high reverse voltage above 175-200°C junction temperature.