Epitaxial growth of lithium niobate thin films by the solid source MOCVD method

Very high-quality single-phase, single-crystal films of LiNbO3 were deposited on both sapphire and LiTaO3 substrates for optical-waveguide applications by the solid-source MOCVD method. Parametric studies have led to the optimization of process-control variables such that reproducible results can be obtain with respect to film composition, crystallinity, and surface roughness. An initial study on the quality of commercial sapphire substrates has revealed variable quality and a heat-treatment procedure which can alter the surface structure. Optical losses were low-but still significant when compared to Ti-indiffused LiNbO3 waveguides.