Research on Threshold Voltage Instability in SiC MOSFET Devices with Precision Measurement

The mechanism of threshold voltage shift was studied. It is believed that the instability in threshold voltage during gate bias stress is due to capture of electrons by the SiC/gate dielectric interface traps and the gate dielectric near interface traps. New experimental platform was designed and built successfully. When positive stress or negative stress is applied to the gate, the change of threshold voltage occur immediately. After stress removal, the recovery of the threshold voltage occur soon. The change and recovery of threshold voltage are very sensitive to time. In order to get accurate threshold voltage drift data after high-temperature gate bias experiment, test of threshold voltage must be carried out immediately after the experiment.