Recovery from plasma etching-induced nitrogen vacancies in p-type gallium nitride using UV/O3 treatments
Geoffrey M. Foster, Andrew D. Koehler, Mona A. Ebrish, James C. Gallagher, Travis J. Anderson, Brenton A. Noesges, L. J. Brillson, Brendan Gunning, Karl D. Hobart, Francis J. Kub
Abstract
Plasma etching of p-type GaN creates n-type nitrogen vacancy (VN) defects at the etched surface, which can be detrimental to device performance. In mesa isolated diodes, etch damage on the sidewalls degrades the ideality factor and leakage current. A treatment was developed to recover both the ideality factor and leakage current, which uses UV/O3 treatment to oxidize the damaged layers followed by HF etching to remove them. The temperature dependent I–V measurement shows that the reverse leakage transport mechanism is dominated by Poole–Frenkel emission at room temperature through the etch-induced VN defect. Depth resolved cathodoluminescence confirms that the damage is limited to first several nanometers and is consistent with the VN defect.