Search

The atmospheric neutron induced single event burnout (SEB) is observed for SiC MOSFETs by conducting irradiation at China Spallation Neutron Source (CSNS) with maximum energy close to 1.6 GeV. The failure is manifested as a sudden loss of voltage blocking ability during irradiation and a melting region is observed for the device with SEB. The SEB failure rates of SiC MOSFETs are calculated based on the experimental results. It shows that the failure rates increase exponentially with operating voltages. The measured failure rates are consistent with the results obtained at the other spallation neutron sources, which proves that the neutron beam line at CSNS is suitable for SEB testing. The information of the secondary ions produced by neutron is obtained through Monte Carlo simulations and the contributors to SEB are analyzed. A simulation method is also applied to calculate SEB failure rate by considering ionization energy deposition of secondary ions in the sensitive region of SiC devices. The simulated failure rates are also consistent with the experimental results. [ABSTRACT FROM AUTHOR]

The mechanisms responsible for atmospheric neutron induced single event burnout (SEB) in commercial silicon carbide (SiC) power MOSFETs were investigated and analyzed. Firstly, based on the atmospheric neutron irradiation spectrometer (ANIS) at the China spallation neutron source (CSNS), accelerated neutron irradiation experiments were carried out to evaluate the dependence of the sensitivity of atmospheric neutrons induced SEB on the drain bias voltage (V DS) in SiC MOSFET. Secondly, microscopic detection and analysis of the burned-out devices were performed at the wafer level by combining microscopy, focused ion beam (FIB) and scanning electron microscope (SEM) to reveal SEB mechanisms inside the semiconductor device. Locally melted morphologies were observed both in the source contact and in the deeper SiC device. Since the melting point of the contact metal is much lower than that of SiC, it is the region where the burnout occurs initially, followed by the vicinity of the n−-drift/n+-drain interface. In addition, combined with the Geant4 calculation and TCAD simulation, the spatiotemporal evolution of the internal electric field and the maximum lattice temperature inside the device after ion incidence were simulated and analyzed. Results show that the strong impact ionization of the carriers induced by the local electric field causes a large amount of energy dissipation in a short time, which eventually leads to thermal damage to the device. • Single event burnout (SEB) of SiC power MOSFET • Broad spectrum-like atmospheric neutron irradiation experiment • Transient device simulations based on TCAD • Secondary ions, radiation effects and SEB mechanism [ABSTRACT FROM AUTHOR]