Reduction in crystallographic tilting of lateral epitaxial overgrown GaN by removal of oxide mask

The lateral overgrowth of GaN was carried out by low-pressure metalorganic chemical vapor deposition. SiO2 mask was removed just before coalescence an d a subsequent lateral overgrowth was carried out to complete the fabricati on of a SiO2-removed lateral epitaxial overgrown (LEO) GaN layer. The cryst allographic tilting of (0002) plane, that was apparent in our standard LEO GaN layers, was absent in SiO2-removed LEO layer and x-ray diffraction meas urement indicated a superior crystallinity for the SiO2-removed LEO layer. These results are attributed to the elimination of the interface between ox ide mask and laterally grown GaN layer. The reduced crystallographic tiltin g in SiO2-removed LEO GaN layer also enhanced the quality of the coalesced fronts, as determined from cathodoluminescence images. (C) 2001 American In stitute of Physics.