1700 V High-Performance GaN HEMTs on 6-inch Sapphire With 1.5 μm Thin Buffer
Xiangdong Li, Junbo Wang, Jincheng Zhang, Zhanfei Han, Shuzhen You, Long Chen, Lezhi Wang, Zilan Li, Weitao Yang, Jingjing Chang, Zhihong Liu, Yue Hao
Abstract
In this work, GaN HEMTs on 6-inch sapphire substrates are successfully demonstrated for potential 1700 V power applications. The 1.5 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> 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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${L}_{\text {GD}}$ </tex-math></inline-formula> of 30 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> highlight a high blocking voltage over 3000 V and a low ON-resistance of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$17~\Omega \cdot $ </tex-math></inline-formula> 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.