Observation and Analysis of Neutron-Induced Single-Event Burnout in Silicon Power Diodes

Annular microvoids formed by neutron-induced single-event burnout (SEB) in Si power diodes were observed by a slice-and-view technique. The axial symmetry of damage region reflects the spatially isotropic thermal diffusion that occurred. Analytical formulas for the local rise in temperature during SEB were derived from the thermal diffusion equation. The local temperature was found to increase in direct proportion to the deposited energy, which was expressed as the time integration of the product of the applied voltage and the SEB current. This current is the result of charges generated by recoil ions and subsequent current-induced avalanche. The diameter of the damage region was estimated using the analytical formulas and the energy associated with Joule heating, which was calculated by technology computer-aided design device simulations, and was found to be comparable in size to the observed annular voids. The SEB current density was also calculated based on the simulated SEB current and the size of the damage region.