17 GW/cm2 AlN-based GaN-channel HEMTs on mono-crystalline AlN substrate

AlN-based GaN-channel HEMTs with MOCVD-grown AlGaN/GaN/AlN epistack were realized on AlN substrates, achieving 400 mA/mm current density at V GS = 1 V and 125 V/μm breakdown voltage (V Br ) scaling. Unlike for similar AlN-on-SiC devices, the high V Br scaling also applies above 1000 V. This is attributed to the significantly reduced AlN-buffer defect density. A record power density of 1.17 GW/cm 2 is extracted from a device with 2.2 kV breakdown voltage. High-voltage switching transients at 0.6 A / 464 V off-state voltage show dispersions effects attributed to the AlN-buffer/ GaN-channel interface quality.