Ultrascaled AIN/GaN HEMT Technology for mm-wave RT Applications

摘要

AIN/GaN heterostructures offer the highest possible 2D electron gas concentration with reasonable mobility while the thinnest possible barrier in single heterostructure based HEMTs. As a result, they are very attractive for ultra-scaled high-speed GaN transistors (ft/fmax > 200 GHz). Indeed our group was the first to demonstrate promising results of AIN/GaN HEMTs: Idmax of 2.3 A/mm, gm,ext of 480 S/mm and gm int of > 1 S/mm, and extrinsic ft/fmax of 52/60 GHz. (Zimmermann 2008 IEEE EDL) However, it has been challenging to harvest these properties due to ohmic contact formation and gate leakage issues. In this program we focused on the following tasks based on our early results: A. Improvement of the AIN/GaN heterostructure grown by MBE to achieve Rsh.