WET ETCHING OF P-GAN FOR CRYSTALLOGRAPHICALLY SMOOTH VERTICAL SIDEWALLS

Other Titles
Abstract

GaN vertical power devices have gained increased attention in recent years due to the advantages over lateral transistors in high breakdown voltage/high current applications as well as thermal performance. Trench etching is a key technology to achieve high-voltage trench-based vertical GaN devices; rough surfaces or sharp corners can lead to device preliminary breakdown due to the electric field crowding. The combination of inductively couple plasma and tetramethylammonium hydroxide (TMAH) etching is commonly utilized in fabrication of smooth and vertical gate planes to minimize surface state charge and achieve high channel mobility. Several groups have reported that TMAH can smooth the n-GaN or UID GaN etched surfaces to reveal m-planes, while negligible etching occurs for p-GaN due to the lack of holes at the surface. In this work, the etch process was found to be diffusion limited for GaN in TMAH. A reaction mechanism for the etch process is proposed. In addition, crystallographically smooth vertical p-GaN sidewalls were achieved by a novel wet etching technique: “hydrogen-passivation-assisted wet etching”. The vertical trench sidewall is preferable for the realization of damage-free high mobility normally-off channel in trench-based vertical GaN devices for high-voltage applications.

Journal / Series
Volume & Issue
Description
Sponsorship
Date Issued
2019-08-30
Publisher
Keywords
Electrical engineering; Materials Science; Chemistry; Crystallographically smooth sidewalls; Damage-free high mobility normally-off channel; GaN vertical power devices; Hydrogen-passivation-assisted wet etching; Tetramethylammonium hydroxide (TMAH)
Location
Effective Date
Expiration Date
Sector
Employer
Union
Union Local
NAICS
Number of Workers
Committee Chair
Xing, Huili Grace
Committee Co-Chair
Committee Member
Jena, Debdeep
Degree Discipline
Materials Science and Engineering
Degree Name
M.S., Materials Science and Engineering
Degree Level
Master of Science
Related Version
Related DOI
Related To
Related Part
Based on Related Item
Has Other Format(s)
Part of Related Item
Related To
Related Publication(s)
Link(s) to Related Publication(s)
References
Link(s) to Reference(s)
Previously Published As
Government Document
ISBN
ISMN
ISSN
Other Identifiers
Rights
Rights URI
Types
dissertation or thesis
Accessibility Feature
Accessibility Hazard
Accessibility Summary
Link(s) to Catalog Record