Burnout Susceptibility of Silicon Power Diodes When Exposed to 14-MeV Neutrons

Neutrons can lead to significant failures in high-voltage power devices; this paper investigates the behavior of a silicon-power PiN diode when exposed to a 14 MeV neutron beam. We present a novel methodology that combines experimental characterization and numerical simulation to examine the effects of ionic species generated by neutron-induced nuclear reactions in semiconductor materials. Experimental measurements were conducted at the Frascati Neutron Generator to explore the device’s failure under controlled irradiation conditions. Subsequently, to comprehend the failure mechanism, a combined simulation approach was adopted. The G4SEE Monte Carlo toolkit was first employed to simulate the interaction of 14 MeV neutrons with the silicon semiconductor material; the resulting secondary particle data were then utilized in three-dimensional electrothermal simulations performed using Silvaco TCAD, leveraging the cylindrical symmetry of the unit cell. The numerical model was validated by comparing the simulation results with the experimental data obtained during the neutron irradiation campaigns. Our study revealed that the (α,25Mg) ion pair is one of the products of the nuclear reaction that interacts most significantly with the electric field within the intrinsic region of the device. This interaction at the critical bias voltage results in a single-event burnout of the diode, as confirmed by experimental observations and numerical analysis. Although the demonstration is based on a monoenergetic 14 MeV source, the methodology is general and can be extended to assess device response under realistic atmospheric neutron spectra.