Evaluating 4H-SiC based commercial MOSFETs power modules

This work deals with static and dynamic measurements performed for 4H-SiC based commercial MOSFETs power modules with voltage rating of 1200 V and current rating of 120 A. First results from engineering samples from Rohm show overall good confidence level that resulted in an ON-resistance of 20-30 mΩ, blocking voltage of 1300-1500 V and threshold voltage of 3.0-3.5 V. Power modules have been tested upto 150 °C (recommended T_j was 125°C) where a threshold voltage shift (i.e., decreases) and decay in the peak transconductance is observed. Overall, energy losses remain approximately unchanged with variation in the device temperature. Turn on and turn off energy losses at 800 V and 190 A (120 A) of 102 (38) and 22 (12) mJ respectively, have been obtained at 300 K. Contrary to Si, SiC power modules did not show reverse recovery neither at different supply voltages nor at different temperatures. A short circuit withstand capability of over 10 μS is witnessed when tested under hard switch fault condition. A small current sharing unbalance has been observed for two parallel power modules as a result of either DC capacitor derating or quasi-symmetrical busbar design when the total current far exceeds the current rating of the power module (i.e., 120 A).