High-Mobility Stable 1200-V, 150-A 4H-SiC DMOSFET Long-Term Reliability Analysis Under High Current Density Transient Conditions

Abstract

For SiC DMOSFETs to obtain widespread usage in power electronics their long-term operational ability to handle the stressful transient current and high temperatures common in power electronics needs to be further verified. To determine the long-term reliability of a single 4H-SiC DMOSFET, the effects of extreme high current density were evaluated. The 4H-SiC DMOSFET has an active conducting area of 40 mm2, and is rated for 1200 V and 150 A. The device was electrically stressed by hard-switching transient currents in excess of four times the given rating (>600 A) corresponding to a current density of 1500 A/cm2. Periodically throughout testing, several device characteristics including $R_{{\bf DS}({\bf on})}$ and $V_{{\bf GS}({\bf th})}$ were measured. After 500 000 switching cycles, the device showed a 6.77% decrease in $R_{{\bf DS}({\bf on})}$ , and only a 132-mV decreased in $V_{{\bf GS}({\bf th})}$ . Additionally, the dc characteristics of the device were analyzed from 25 to 150 °C and revealed a 200-mV increase in on-state voltage drop at 20 A and a 2-V reduction in $V_{{\bf GS}({\bf th})}$ at 150 °C. These results show this SiC DMOSFET has robust long-term reliability in high-power applications that are susceptible to pulse over currents, such as pulsed power modulators and hard-switched power electronics.