Nonpolar m-plane GaN on patterned Si(112) substrates by metalorganic chemical vapor deposition

The concept of nonpolar (1 (1) over bar 00) m-plane GaN on Si substrates has been demonstrated by initiating growth on the vertical ((1) over bar(1) over bar1) sidewalls of patterned Si (112) substrates using metalorganic chemical vapor deposition. The Si(112) substrates were wet-etched to expose {111} planes using stripe-patterned SiNx masks oriented along the [(1) over bar 10] direction. Only the vertical Si ((1) over bar(1) over bar1) sidewalls were allowed to participate in GaN growth by masking other Si{111} planes using SiO2, which led to m-plane GaN films. Growth initiating on the Si((1) over bar(1) over bar1) planes normal to the surface was allowed to advance laterally and also vertically toward full coalescence. InGaN double heterostructure active layers grown on these m-GaN templates on Si exhibited two times higher internal quantum efficiencies as compared to their c-plane counterparts at comparable carrier densities. These results demonstrate a promising method to obtain high-quality nonpolar m-GaN films on large area, inexpensive Si substrates. (C) 2009 American Institute of Physics. [doi:10.1063/1.3225157]