Substrate misorientation dependence of the hexagonal phase inclusion in cubic GaN films grown by metalorganic vapor phase epitaxy

The metalorganic vapor phase epitaxial (MOVPE) growth of cubic GaN layers on misoriented GaAs (001) substrates, the faces of which were tilted from (001) toward [11̄0] or [110] by 4°, was performed in order to investigate the effect of the substrate misorientation on the inclusion of hexagonal phase in the cubic GaN layer. The sample grown on the tilted surface toward [11̄0] showed an enhanced generation of the hexagonal domain on the (11̄1) face, whereas the hexagonal domain on the (1̄11) face was suppressed. The sample grown on the tilted surface toward [110] showed the generation of the hexagonal domains on both the (11̄1) and (1̄11) faces with an equal magnitude. It is suggested that the generation of hexagonal domains may be suppressed when the exposure of the (11̄1) or (1̄11) faces by the thermal damage of the substrate surface is reduced.