The Formation of Smooth Facets on Wet-Etched Patterned Sapphire Substrate

Abstract

In this study, rectangle-shaped SiO2 hard masks with various orientations were employed to find various facets on wet-etched patterned sapphire substrate (PSS). Seven facets (A, B, B-1, B-2, D-1, D-2 and E) were observed after etching. The surfaces of A, B and E-facets were smooth. Their plane indexes were {13 (4) over bar7}, {10 (1) over bar4} and {12 (3) over bar5}, respectively. On the other hand, the surfaces of B-1, B-2, D-1 and D-2-facets were not smooth, with some ambiguous stripes, which were investigated by using "zigzag triangle" hard mask. A large triangle-mask was employed to investigate smooth facets and the GaN epitaxial behavior. It was found that most of the growth of zincblende GaN was initiated not from A and B-facets but E-facets. (C) 2013 The Electrochemical Society. All rights reserved.