Growth of highly oriented LiTaO 3 thin film on Si with amorphous SiO 2 buffer layer by pulsed laser deposition

Abstract

High-quality single-phase, c-axis textured LiTaO 3 thin films have been deposited on Si(100) substrate with amorphous SiO 2 buffer layer for optic waveguide application by pulsed laser deposition under optimized conditions of 30 Pa oxygen pressure and 650 °C. The amorphous SiO 2 buffer layer with a thickness of 100 nm was coated on the Si(100) by thermal oxidation at 1000 °C. Li-enriched LiTaO 3 ceramic target was used during the deposition. In order to study the influence of oxygen pressure on the orientation, crystallinity and morphology, different oxygen pressures (10 Pa, 20 Pa, 30 Pa and 40 Pa) were used. X-ray diffraction (XRD) results showed that LiTaO 3 thin films exhibited highly c-axis orientation under 30 Pa. It was observed by scanning electron microscopy (SEM) that the as-grown film in the optimal conditions was characterized by a dense and homogeneous surface without cracks, and the average grain size was in the order of 25 nm.