Conventional and pendeo-epitaxial growth of GaN(0 0 0 1) thin films on Si(1 1 1) substrates

Abstract

Single-crystal wurtzitic GaN(0 0 0 1) films have been grown via conventional methods on high-temperature AlN(0 0 0 1) buffer layers previously deposited on 3C-SiC(1 1 1)/Si(1 1 1) substrates using metal organic vapor phase epitaxy (MOVPE). Formation of the 3C-SiC transition layer employed a carburization step and the subsequent deposition of epitaxial 3C-SiC(1 1 1) on the Si(1 1 1) surface using atmospheric pressure chemical vapor deposition (APCVD) for both processes. Similar films, except with significantly reduced dislocation densities, have been grown via pendeo-epitaxy (PE) from the (1 1 2 ̄ 0) sidewalls of silicon nitride masked, raised, rectangular, and [1 1 ̄ 0 0] oriented GaN stripes etched from films conventionally grown on similarly prepared, Si-based, multilayer substrates. The FWHM of the (0 0 0 2) X-ray diffraction peak of the conventionally grown GaN was 1443 arcsec. The FWHM of the photoluminescence (PL) spectra for the near band-edge emission on these films was 19 meV. Tilting in the coalesced PE-grown GaN epilayers of 0.2° was confined to the areas of lateral overgrowth over the masks; no tilting was observed in the material suspended above the trenches. The strong, low-temperature PL band-edge peak at 3.456 eV with an FWHM of 17 meV in the PE films was comparable to that observed in PE GaN films grown on AlN/6H-SiC(0 0 0 1) substrates.