Defect reduction in GaN regrown on hexagonal mask structure by facet assisted lateral overgrowth

Abstract

It is demonstrated that the threading dislocation density in GaN is considerably reduced by Facet Assisted Epitaxial Lateral Overgrowth (FACELO) on a hexagonal honeycomb grid structure. We observed a more isotropic strain and curvature development in the GaN layer by such a mask geometry. Here, we describe how to achieve a nearly dislocation-free surface by a fairly complex variation of the epitaxial growth parameters. Eventually, dislocation analysis of epitaxially grown GaN using an HCl vapor phase etching process resulted in dislocation densities below 106cm−2.