1700 V High-performance GaN HEMTs on 6-inch Sapphire with 1.5 μm Thin Buffer

In this work, GaN HEMTs on 6-inch sapphire substrates are successfully demonstrated for potential 1700 V power applications. The 1.5 μm GaN buffer features a well-controlled crystal quality and uniformity. Benefiting from the insulating sapphire substrate, the buffer vertical leakage channel is cut off, and the lateral parasitic channel at the epitaxy/substrate interface is also significantly suppressed. The fabricated d-mode HEMTs with L GD of 30 μm highlight a high blocking voltage over 3000 V and a low ON-resistance of 17 Ω·mm. The thin-buffer GaN-on-sapphire technology can significantly reduce the epitaxy and processing difficulties, reduce cost, and enable GaN as a strong competitor for 1700 V and even higher-level power applications.