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

摘要

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 mΩ-cm~2 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 V_(GS) = 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 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°C difference in die temperature, which suggests even current sharing and temperature stable device operation.