Recovery from plasma etching-induced nitrogen vacancies in p-type gallium nitride using UV/O3 treatments

Plasma etching of p-type GaN creates n-type nitrogen vacancy (V-N) 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/O-3 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 V-N defect. Depth resolved cathodoluminescence confirms that the damage is limited to first several nanometers and is consistent with the V-N defect.