Evaluation of 4H-SiC DMOSFETs for High-Power Electronics Applications

In this paper, large area (0.18cm(2)) SiC DMOSFETs with 1.2 kV and 20 A rating are evaluated for power electronic switching applications. A drain-to-source voltage drop V-DS of 2 V at a forward drain current of 20 A (J(D) = 110 A/cm(2)) was obtained and a specific on-resistance of 18 m Omega-cm(2) was extracted at room temperature. The device on-resistance was measured up to 150 degrees C and initially decreases with increasing temperature, but remains relatively flat over the entire temperature range, demonstrating stable device behavior. High voltage blocking of 1.2 kV between 25 degrees C and 150 degrees C is also demonstrated with a gate-to-source voltage V-GS = 0 V. The drain leakage current under reverse bias and high temperature stress is shown to increase from 10 mu A at 25 degrees C to 27 mu A at 150 degrees C while maintaining the full blocking rating of the device. Experimental results from double-pulse clamped inductive load tests are presented demonstrating fast high voltage and high current switching capability. High voltage resistive-switching measurements on parallel connected SiC DMOSFETs were performed with V-DS having rise and fall times of 49 and 74 ns respectively. Thermal camera images taken of parallel connected DMOSFET die during repetitive switching operation with V-DS = 420 V, I-DS = 25 A and a 40% duty cycle shows a 2 degrees C difference in die temperature, which suggests even current sharing and temperature stable device operation.