GaN Switching Devices for High-Frequency, KW Power Conversion

Large periphery GaN HEMT switches were designed and fabricated using field-plated gates on semi-insulating SiC substrates. The device layout was designed to handle both large currents and support the high bias conditions required for 100V switching. Blocking voltage of >200V was achieved on devices with saturation currents of 0.8A/mm. The switching characteristics of devices with gate periphery of 30-60mm were measured with both resistive and inductive loads, and showed rise- and fall-times of <25ns. Turn-on and turn-off switching losses of 11 muJ were measured at 100V/11A switching in resistive load. Maximum switching currents of 8 and 23A were measured with an inductive load at 60 and 40V, respectively. These results are the first demonstration of high-power (920W), high-speed (<25ns) switching of GaN devices for kW power conversion applications