Photostimulated direct etching of GaN has been demonstrated with extremely high etching rate up to 135 nm/pulse. The process consists of laser irradiation and ex-situhydrochloric acid treatment. Not only deep etching but also a highly planarized surface are obtained by an increase in laser fluence and the number of pulses. Seven-pulse irradiation at 1 J/cm2 decreases surface average roughness (Ra) to 2 nm from 10 nm of the untreated sample. No deep-level emission (450-600 nm) is detected in photoluminescence measurement on the samples irradiated with laser fluences as high as 3 J/cm2.
Applied Physics A: Materials Science & Processing
- Pub Date:
- PACS: 81.65.Cf