Low extended defect density nonpolar m-plane GaN by sidewall lateral epitaxial overgrowth

Abstract

Sidewall lateral epitaxial overgrowth (SLEO) is demonstrated by metal organic chemical vapor deposition for nonpolar {11¯00} m-plane GaN films. m-plane GaN films were grown by metal organic chemical vapor deposition on m-plane 6H SiC substrates with an AlN initiation layer. Subsequently, an SiO2 stripe dielectric pattern was formed with 2μm window openings parallel to the [112¯0] a-direction and an 8μm mask and then the m-plane GaN was etched through the window openings to reveal Ga-face (0001) and N-face (0001¯) sidewalls. The SLEO growth was achieved in two growth steps—lateral growth from the sidewalls and subsequent growth through and then over the dielectric mask openings. In comparison to planar m-plane GaN films grown on 6H SiC, the threading dislocation density was reduced from low 1010to3×108cm−2 and the stacking fault density was reduced by one order of magnitude.