A self-disappear-mask for epitaxial lateral overgrowth of GaN films

Abstract

Although GaN epitaxial lateral overgrowth (ELOG) technology has been developed for some years, this is the first effort to integrate it with two-dimensional (2D) materials owing to their superior qualities. The present study investigates a novel ELOG method for two-step GaN epitaxial lateral overgrowth (2S-ELOG) in metal organic chemical vapor deposition (MOCVD) employing a self-disappearing graphene mask. Photolithography is used to mask the graphene layers that are produced on the GaN through plasma accelerated chemical vapor deposition (PECVD). By adjusting the temperature to partly dissolve the substrate surface, the graphene vanished without interfering with the ELOG mode. Not only did the GaN generated using this approach retain the ELOG feature, but it also exhibited benefits in terms of stress relaxation and threading dislocation densities (TDDs) reduction. This study demonstrates that employing a graphene mask, self-disappearing-mask epitaxial lateral overgrowth (SDM-ELOG) technology may be used to apply a 2D nanoscale material mask to improve the crystal quality of a 3D material.