Excimer-Laser-Induced oxidation of GaN epilayer

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/cm(2) which was much lower than the threshold fluence for GaN decomposition or damage (above 600 mJ/cm(2)). 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 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.