Reliability of reverse properties of power semiconductor devices:: Influence of surface dielectric layer and its experimental verification

Reliability of reverse properties of power semiconductor devices is an important condition for their practical application. Usual standard tests do not reveal total information concerning the technological genetic aspects of devices production. These aspects can be linked with individual technological operations, most frequently with preparation of semiconductor surface and its protection by dielectric layers. Properties of dielectric layers influence the time stability of reverse currents by means of a change of dielectric permittivity. This article analyses some physical causes of the time-instable behaviour of devices and also presents a special method and equipment for reliable tests.