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

Abstract

In this paper, large area (0.18cm2) SiC DMOSFETs with 1.2 kV and 20 A rating are evaluated for power electronic switching applications. A drain-to-source voltage drop VDS of 2 V at a forward drain current of 20 A (JD = 110 A/cm2) was obtained and a specific on-resistance of 18 mΩ-cm2 was extracted at room temperature. The device on-resistance was measured up to 150°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°C and 150°C is also demonstrated with a gate-to-source voltage VGS = 0 V. The drain leakage current under reverse bias and high temperature stress is shown to increase from 10 μA at 25°C to 27 μA at 150°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 VDS 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 VDS = 420 V, IDS = 25 A and a 40% duty cycle shows a 2°C difference in die temperature, which suggests even current sharing and temperature stable device operation.