Carrier capture and emission properties of silicon interstitial defects in near SiC/SiO2 interface region

As the origin of near interface traps in silicon carbide (SiC)/SiO2 system, Si interstitial defects can affect the stability of SiC metal-oxide-semiconductor field-effect transistor (MOSFET) devices. Models are established based on the density functional theory to investigate the carrier capture and emission properties of Si interstitial defects with two configurations in the near interface region on SiO2 side. Calculation results indicate the capture ability of Si-Si-Si configuration is strong for holes but weak for electrons, whereas that of Si-Si-O is strong for holes and electrons. Hence, these two configurations affect the stability of p-channel MOS and n-channel MOS devices in different degrees. For the charge emission ability, Si-Si-Si configuration has strong emission ability for electrons and holes, whereas Si-Si-O has a strong ability to emit electrons but weak ability to emit holes. The discrepancy of charge emission ability makes each configuration affect the stability of device in different ways, including charge exchange with channel and Coulomb scattering. This work helps understand the mechanisms of deterioration in reliability caused by SiC near-interface oxide defects.