Summary: Digital Etching of III-N Materials Using a Two-Step
RUSSELL D. DUPUIS,2
and MILTON FENG3
1.--Electrical and Computer Engineering, University of California, San Diego, 9500 Gilman
Drive, La Jolla, CA 92093-0407. 2.--Electrical and Computer Engineering, Georgia Institute of
Technology, 777 Atlantic Drive, Atlanta GA 30332-0250. 3.--Center for Micro and Nanoelec-
tronics, University of Illinois at Urbana-Champaign, 208 N. Wright Street, Urbana IL 61801.
A two-step digital etch technique, based on an argon plasma exposure followed
by a 0.2 M boiling KOH surface treatment, is shown to be effective for etching
III-N materials. Etching takes place as a result of the fact that damaged
nitride material, whose depth can be controlled by the argon reactive ion
etching (RIE) plasma, is susceptible to removal in heated solutions of KOH,
which has been demonstrated for GaN, AlGaN, and InGaN. The process is
shown to be highly linear across a number of digital etch cycles and capable of
producing smooth surface morphologies.