Effect of Heavy-Ion-Induced Latent Damage on SiC MOSFETs’ Gate Reliability

This study investigated the impact of latent damage induced by heavy ions on the gate reliability of 1200 V SiC MOSFETs. Irradiation was conducted using Kr and Ta ions, with linear energy transfer (LET) of 38.85 MeV·cm²/mg and 86.03 MeV·cm²/mg, respectively. Devices exhibiting latent damage underwent a 1000-hour assessment at a gate voltage of 20 V. The findings revealed a significant increase in gate leakage current after the assessment, which is presumed to be caused by trap-assisted tunneling effects. Furthermore, latent damage resulted in a reduction of gate breakdown voltage by approximately 50%. The research also indicated that latent damage did not significantly affect the threshold voltage and transfer characteristics of the devices, suggesting that they retained a degree of gate control capability. Two potential explanations are proposed, providing new insights into the long-term reliability evaluation of SiC MOSFETs post-irradiation.