Dislocation reduction in GaN grown on stripe patterned r-plane sapphire substrates

Abstract

Extended defect reduction in GaN can be achieved via direct growth on stripe patterned (1(-)1 02) r-plane sapphire substrates by metal organic chemical vapor deposition. The striped mesa is along [11 (-)2 0] with two etched sides in {0001} and {1 (-)1 01} faces. GaN grown on both etched facets in epitaxy exhibit different crystallographic relationships with sapphire substrate which are (1 (-)1 02)(sapphire)parallel to(11 (-)2 0)(GaN) and [11 (-)2 0](sapphire)parallel to[ (-)1 100](GaN), and (0001)(sapphire)parallel to(0001)(GaN) and [11 (-)2 0](sapphire)parallel to[ (-)1 100](GaN), respectively. The dislocation densities can be significantly reduced through epitaxial growth on the inclined lateral faces of mesas. Dislocation density in the order of similar to 10(7) cm(-2) can be achieved in the tilted GaN. (C) 2007 American Institute of Physics.