AlGaN/GaN HEMTs for high voltage applications

In this paper, we report on the development of normally-on high electron mobility transistors (HEMTs) based on AlGaN/GaN semiconductors, on semi-insulating SiC and Si substrates for high voltage applications (U = 100 - 600 V). Transistors with a total gate periphery of 240 mm achieve a breakdown voltage of 600 V and 120 V, for a device with a gate drain distance of 15 µm and 4 µm, respectively. A maximum drain current of 54 A measured for a corresponding gate source voltage of 2 V. The Schottky gate supports a bias of + 5 V and the drain current is greater than 83 A. Breakdown voltage mapping of the large transistors, across the 3" SiC substrate, and also from wafer to wafer, shows a yield > 65 %, reflecting the uniformity of the process for the large area high voltage devices.