248 nm excimer-laser-induced native oxide film formation on GaN surface

Abstract

This paper describes an investigation into using an excimer laser to induce the formation of native oxide film on GaN surfaces. It was revealed that laser-induced oxidation reaction of GaN occurred at 250 mJ/cm2 which was much lower than the threshold fluence for decomposition or damage (above 600 mJ/cm2) of GaN. The laser induced oxidation rate could reach 750 nm/h which was much higher than that with conventional thermal oxidation method (about 20 nm/h). It was postulated that laser photon excitation of electron-hole pairs was the main mechanism responsible for enhancing the oxidation reaction of GaN. Using glancing-angle Xray diffraction, the induced oxide was determined to be monoclinic β-Ga2O3. The morphology of the laserinduced oxide surface was smooth and uniform. The process has potential applications in the fabrication of GaN-based electronic and optoelectronic devices.This paper describes an investigation into using an excimer laser to induce the formation of native oxide film on GaN surfaces. It was revealed that laser-induced oxidation reaction of GaN occurred at 250 mJ/cm2 which was much lower than the threshold fluence for decomposition or damage (above 600 mJ/cm2) of GaN. The laser induced oxidation rate could reach 750 nm/h which was much higher than that with conventional thermal oxidation method (about 20 nm/h). It was postulated that laser photon excitation of electron-hole pairs was the main mechanism responsible for enhancing the oxidation reaction of GaN. Using glancing-angle Xray diffraction, the induced oxide was determined to be monoclinic β-Ga2O3. The morphology of the laserinduced oxide surface was smooth and uniform. The process has potential applications in the fabrication of GaN-based electronic and optoelectronic devices.