GROWTH AND CHARACTERIZATION OF C-ORIENTED LiNbO3 THIN FILMS ON Si (100) BY PLD

Abstract

Lithium niobate ( LiNbO 3) thin film is an important material for optical waveguide. Recently, particular attention has been paid to the application of LiNbO 3 (LN) thin films. To develop and fabricate integrated optical devices, the growth of thin LN epitaxial films onto silicon substrate is of great importance and particularly attractive. In this paper, LN thin film was grown by pulsed laser deposition (PLD). Stoichiometric LN ceramic is used as a target. Amorphous SiO 2 buffer layer was coated on Si (100) wafer by in-situ themal oxidation before the deposition. The optimized condition of growing LN film on Si (100) by PLD is found: O 2 pressure 30 Pa, substrate temperature 600°C. Only (006) reflection of LN was observed besides the (002) reflection of silicon substrate from XRD pattern. The FWHM (~0.21°) of (006) reflection peak is much narrower than the value reported by Lee [1]. The results of XRD measurement indicate that the LN film was epitaxially grown along the c-axis. Transmission electron microcopy (TEM) patterns confirm that the film has superior crystalline quality. The optical waveguiding properties of the films were demonstrated by a prism coupler method. Fully c-oriented thin film could be grown on silicon substrate by PLD without the buffer layer and the induced electric field.