Single Crystalline Thin Films of Natural Superlattice Oxide, InGaO₃(ZnO)_m, Grown by instant Solid-Phase Epitaxy(II)

Abstract

In order to clarify the growth mechanism of single-crystalline thin film of InGaO₃(ZnO)_m by reactive solid-phase epitaxy, we investigated the structural changes of the InGaO₃(ZnO)₅/epi-ZnO bi-layer grown on (111) YSZ during high-temperature annealing using HREM. The ZnO epitaxial layer is no longer detected when it is annealed at 1000°C while a 50nm-thick single-crystalline InGaO₃(ZnO)₅ layer was formed just from the substrate surface. It implies that the solid-phase reaction between the polycrystalline InGaO₃(ZnO)₅ and the ZnO epitaxial layer occurs at temperatures greater than 1000°C, which leads to the formation of the epitaxial layer. Finally, an almost perfect superlattice structure of InGaO₃(ZnO)₅ is formed over the entire area of the film after the annealing at 1400°C.