March 13th (Thu) @ 11:00 am: "Optimizing Process Technologies for Nitrogen-Polar GaN Devices," Emmanuel Kayede, ECE PhD Defense

Location: Materials Research Laboratory (MRL), Room 2053 
Zoom Meeting: https://ucsb.zoom.us/j/89117083607 | Passcode: 900571
Research Area: Electronics & Photonics

Abstract

As interest in communication and imaging at millimeter-wave (mm-wave) frequencies grows, the demand for high-performance transistor technologies becomes increasingly critical. Nitrogen-polar gallium nitride high-electron-mobility transistors (GaN HEMTs) have emerged as promising candidates for solid-state mm-wave power amplifiers, offering significant potential for high-frequency applications.

This defense will present the development of process technologies to improve future GaN HEMTs for mm-wave applications. The increased chemical reactivity of the N-polar GaN surface eables using wet etching in fabricating GaN HEMTs, including high selectivity etching of GaN over AlGaN. This innovation facilitates the development of N-polar GaN deep recessed HEMT with smooth AlGaN gate barrier layers via wet-etching. Furthermore, a model will be shared to illustrate the inverse relationship between wet etching and the N-polar GaN layers grown on miscut sapphire substrates.

Furthermore, the solutions to the challenges of achieving high Schottky barrier heights on N-polar GaN will be presented. This is accomplished using atomic-layer-deposited titanium nitride (TiN) and ruthenium (Ru) as key materials. Pulse I-V measurements used to investigate traps in the Schottky metal/GaN system will be shared and their implications discussed.

Bio

Emmanuel Kayede is a PhD candidate in the ECE department at UCSB, advised by Prof. Umesh Mishra. He received his BS in ECE from UCSC in 2018 and his MS in ECE from UCSB in 2021.

Hosted By: ECE Professor Umesh Mishra

Submitted By: Emmanuel Kayede <ekayede@ucsb.edu>