May 20 (Mon) @ 11:30am: "Advances in Nitrogen-polar GaN HEMTs Enabling Adoption in mm-Wave Applications," Henry Collins, ECE PhD Defense

Date and Time
Engineering Science Building (ESB), Room 2001


Emerging high-frequency technologies such as satellite communication, 5G telecommunication, and autonomous vehicles necessitate the development of mm-wave power amplifiers. In this work, performance of Nitrogen-polar gallium nitride high electron mobility transistors (N-polar GaN HEMTs) was improved in three key domains. First, the figure of merit ft•LG was increased by over 20% by employing a gate dielectric with a tailored profile. Next, a Schottky-gate HEMT on a low-cost Sapphire substrate achieved a record 53.4% PAE with associated 3.7 W/mm of output power at 94 GHz. Finally, a corrugated channel HEMT was used for high, bias-insensitive, low-power linearity at 30 GHz. These improvements contribute to the growing appeal of N-polar GaN HEMTs for next-generation high-frequency applications.


Henry Collins is a Ph.D. candidate in the ECE department at UCSB. He earned his MS degree in electrical engineering from UCSB in 2020 and his BS degree in electrical engineering from North Carolina State University in 2018. His interests include N-polar GaN HEMTs, semiconductor device processing, and device characterization.

Hosted by: Professor Umesh Mishra

Submitted by: Henry Collins <>