High performance GaN HEMTs for mmWave applications

摘要

A robust, high performance, and high yield process for GaN AlGaN HEMTs is demonstrated for mmWave applications. A key element of the process is a refractory Ohmic contact with sharp edges, smooth surface morphology, and stable contact resistance up to 350 ℃. High frequency operation is enabled with 180nm e-beam written T-gates. Our process resulted in record performance at mmWave with a baseline epitaxial structure design on both 4H and 6H SI-SiC substrates. A reproducible RF performance, and a high PCM device yield of greater than 85% was successfully scaled from 2″ to 3″ SI-SiC substrates.