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

The concept of non-polar (11bar00) m-plane GaN on Si substrates has been demonstrated by initiating growth on the vertical (1bar1bar1) 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 SiN x masks oriented along the [1bar10] direction. Only the vertical Si (1bar1bar1) 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 (1bar1bar1) planes normal to the surface was allowed to advance laterally and also vertically towards full coalescence. The full width at half maximum values for the GaN mplane x-ray diffraction rocking curves were 9 and 27 arcmin when rocked toward the GaN a-axis (parallel to stripes) and the GaN c-axis (perpendicular to stripes), respectively. Room-temperature photoluminescence showed strong band-edge emission with an intensity comparable to that of laterally overgrown c-plane GaN. 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 highquality non-polar m-GaN films on large area, inexpensive Si substrates.