A Study on the Reliability and Stability of High Voltage 4H-SiC MOSFET Devices
Gate oxide reliability measurements of 4H-SiC DMOSFETs were performed using the Time Dependent Dielectric Breakdown (TDDB) technique at 175°C. The oxide lifetime is then plotted as a function of the electric field. The results show the projected oxide lifetime to be > 100 years at an operating field of ~3 MV/cm. Device reliability of 2.0 kV DMOSFETs was studied by stressing the gate with a constant gate voltage of +15 V at a temperature of 175°C, and monitoring the forward I-V characteristics and threshold voltage for device stability. Our very first measurements show very little variation between the pre-stress and post-stress conditions up to 1000 hrs of operation at 175°C. In addition, forward on-current stressing of the MOSFETs show the devices to be stable up to 1000 hrs of operation.
Robert P. Devaty, David J. Larkin and Stephen E. Saddow
S. Krishnaswami et al., "A Study on the Reliability and Stability of High Voltage 4H-SiC MOSFET Devices", Materials Science Forum, Vols. 527-529, pp. 1313-1316, 2006