Layer-by-layer oxidation of InN(0001) thin films into body-center cubic In2O3(111) by cycle rapid thermal annealing

Abstract

We report on a study of In₂O₃ thin films obtained by post-growth thermal oxidation of InN(0001) using rapid thermal annealing (RTA) and cycle-RTA (CRTA). The crystal qualities of both the resultant In₂O₃ and the remaining InN were significantly improved by using CRTA instead of RTA. Body-center cubic (bcc) In₂O₃, consisting of two In₂O₃(111) variants in-plane rotated 60° with respect to each other, was epitaxially grown on InN(0001). The in-plane orientations were determined as In₂O₃[01]//InN[110] and In₂O₃[01]//InN[20] for the two In₂O₃(111) variants. Microscopic and spectroscopic analyses, together with the effect of Si₃N₄ encapsulations, provide evidence that the oxidation of InN is realized by oxygen inward diffusion. The oxygen inward diffusion is slowed down and the thermal decomposition of InN is suppressed by using CRTA, which in turn leads to a layer-by-layer oxidation of InN.