Influence of electron irradiation on the power cycling lifetime of SiC MOSFETs

Purpose SiC MOSFETs are widely used in aerospace and power electronics owing to their superior electrical properties, yet they suffer from combined threats of space radiation and thermo-electrical stress fatigue. This study aims to explore the influence of electron irradiation on the power cycling lifetime of SiC MOSFETs and reveal the corresponding failure mechanisms, offering a theoretical basis for the reliability evaluation of SiC MOSFETs in space radiation environments. Design/methodology/approach Experiments were conducted using 10 MeV electron irradiation at doses of 3 Mrad, 5 Mrad and 10 Mrad(Si), followed by forward-mode power cycling tests. Electrical parameters including threshold voltage and on-resistance were monitored periodically. Optical microscopy was adopted to characterize bond wire and solder layer damage. Electro-thermal-mechanical coupling simulation and Geant4 simulation were applied to analyze the internal stress distribution and energy deposition, clarifying the failure evolution process. Findings Electron irradiation induces negative drift of threshold voltage and reduction of on-resistance via gate oxide charge trapping. During power cycling, threshold voltage shifts positively and on-resistance rises significantly with cycling count, and higher irradiation dose aggravates the drift amplitude. Electron irradiation drastically shortens the power cycling lifetime, which is reduced by 60% at 10 Mrad compared with unirradiated devices. Irradiation creates lattice defects in the solder layer, forming voids under cyclic thermal stress, which intensifies stress concentration at bond wire-chip joints and accelerates bond wire lift-off as the final failure mode. Originality/value This study systematically reveals the synergistic degradation mechanism of electron irradiation and power cycling on SiC MOSFETs, distinguishing chip-level electrical parameter degradation and package-level mechanical failure. It provides key data and mechanistic support for the lifetime prediction and reliability optimization of SiC power devices in space applications.