A method for determining the susceptibility of semiconductor devices to damage from an electromagnetic pulse (EMP) due to induced thermal second breakdown is described. The method can be used as a nondestructive screening test. It is based on the increase in junction reverse breakdown voltage with temperature and can be used to find the most EMP resistant devices of a given device type. A mathematical explanation is presented, and other tentative applications are proposed.

Puise injection tests on germanium gold-bonded diodes showed that failure due to second breakdown may occur at lower power levels in the forward direction than In the reverse direction. The result is shown to be due to the hemispherical geometry of the junction and the associated spatial variation of the conduc tivity modulation. Variation between devices of different manufacturers is noted.