Energy Dependence of Atmospheric Neutron-Induced Failures in Silicon Carbide Power Devices

Abstract

A time-of-flight measurement technique is used to determine energy-dependent neutron cross sections of silicon carbide power devices exposed to a beam that approximates atmospheric neutrons up to 600 MeV. The Irradiation of Chip Electronics (ICE)-II neutron beam at the Los Alamos Neutron Science Center (LANSCE) is used during these experiments. The measurements show that a wide range of neutron energies are likely to cause device failures close to the rated voltage, from neutron interactions with lattice atoms within the active device volume. The data indicate that the energy-dependent cross sections are relatively large, revealing a high probability for a few percent of the neutron–lattice atom interactions to give rise to a failure when the device is biased close to its rated voltage. Additionally, knowledge of the neutron energies and associated cross sections giving rise to failures within these devices provide insights regarding the critical charges and the sensitive volumes of these devices as a function of neutron energy for single-event burnouts. Lastly, the energy-dependent cross sections provide a preliminary set of data to calculate a correlation factor between failure rates obtained using a broad energy neutron source, and the commonly used mono-energetic high-energy proton beams, utilized due to their wider availability for determining bias dependent failure-in-time curves.