Selective Area Growth of Semipolar (202̄1) and (202̄1̄) GaN Substrates by Metalorganic Vapor Phase Epitaxy

Abstract

We carried out the selective area growths of GaN on semipolar (202̄1), (202̄1̄), and related non- and semi-polar GaN substrates by metalorganic vapor phase epitaxy. By changing the growth parameters and directions of the SiO2 stripe mask, the differences in GaN structures between the growths on the different substrates were investigated. In the case of the stripes ∥ a-axis, anisotropic GaN structures with (0001̄) and (101̄1) facets were obtained for all the non- and semi-polar GaN substrates. On the other hand, in the case of the stripes ⊥ a-axis, isotropic GaN structures were obtained for the (202̄1) and (202̄1̄) GaN substrates. However, the GaN structures between them were quite different. After 120 min of growth, {112̄0} and (202̄1̄) facets markedly expanded for the (202̄) and (202̄1̄) GaN substrates, respectively. Moreover, by exploiting the effect of growth temperature, the growth of a continuous (202̄1̄) GaN layer with voids was realized.