HETEROEPITAXY OF LINBO3 AND LINB3O8 THIN-FILMS ON C-CUT SAPPHIRE

The crystal growth of LiNbO3 thin films with ionic bonds has been investigated to compare to that of materials with hybridized orbit. We find that LiNb3O8 (Li poor phase) is formed well epitaxially on C-cut sapphire, under the same conditions as the LiNbO3 thin film can be formed on R-cut sapphire. The LiNb3O8 formed at the interface is decomposed at high substrate temperatures, and transformed to the epitaxial LiNbO3. Part of the LiNb3O8 phase remains at the surface and disturbs the crystallinity of the epitaxial layer. The polycrystalline LiNb3O8 layer is decomposed by annealing at 800-degrees-C. The LiNb3O8 epitaxial film is also transformed to an epitaxial LiNbO3 layer with double domains.