Excimer-Laser-Induced Oxidation of GaN Epilayer

Abstract

The 248 nm excimer-laser-induced oxidation of GaN epilayers with assisting oxygen was investigated. The mechanism of laser-induced oxide formation was discussed. It was revealed that the laser-induced oxidation reaction of GaN occurred at 250 mJ/cm2 which was much lower than the threshold fluence for GaN decomposition or damage (above 600 mJ/cm2). It was postulated that laser light excitation of electron–hole pairs was the main mechanism responsible for the enhancement of the oxidation reaction of GaN. Using glancing-angle X-ray diffraction, the induced oxide was determined to be monoclinic β-Ga2O3. It was also found that with an increase in laser pulse number, the oxygen concentration in the oxide film increased to a value corresponding to Ga2O3. The morphology of the laser-induced oxide surface was smooth and uniform. The process has the potential for being applied in the fabrication of GaN-based electronic and optoelectronic devices.