Development of Low RON,Diff, 12 kV, 4H-SiC GTOs For High-Power and High-Temperature Applications

In this paper, we report our recently developed 1 × 1 cm2, 12 kV SiC GTOs with a very low differential on-resistance (RON,Diff) of 4 mΩ·cm2 with respect to the device active area at high injection level current of 100 A/cm2 or higher, which is more than a 40% reduction from our previously reported work. This significant reduction in the on-resistance was attributed to an improvement of carrier lifetime in the SiC bulk region. The SiC GTO was wire-bonded and attached to a high-voltage package before the high-temperature measurement. Forward characteristics of the device were then measured using a Tektronics 371 curve tracer from room temperature up to 400°C. Over the temperature range, the RON,Diff of the 4H-SiC GTO increased modestly from 4 mΩ·cm2 at 20°C to 4.7 mΩ·cm2 at 400°C, while the forward voltage drop at 100 A decreased slightly from 3.97 V at 20°C to 3.6 V at 400°C. The gate to cathode blocking voltage (VGK) was measured using a customized high-voltage test set-up. The leakage current was measured 0.66 μA at a VGK of 12 kV at 20°C.