The Study of Lithium Niobate Thin Films by RF Sputtering Method

• Main Authors: Fu-Tsai Hwang, 黃富財
• Other Authors: none
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/35494896255427060073

博士 === 國立中央大學 === 光電科學研究所 === 94 === Abstract Very high quality LiNbO3 films were deposited on both silicon and quartz substrates for the applications of surface acoustic wave and optical waveguide by RF magnetron sputtering. We have investigated the dependence of the surface morphology, texture, crystallinity, thickness, refractive index, extinction coefficient properties with the sputtering parameters and annealing process. The optimum deposition temperature was measured by differential thermal analysis. The crystallinity was examined by x-ray and low angle x-ray diffractometer (XRD). The roughness of LiNbO3 thin films was examined by atomic force microscopy (AFM). AFM and XRD measurements were used to investigate the mechanisms of the variation in the surface morphology and crystallinity of LiNbO3 thin films.The optimum deposition temperature was found to be about 575℃. In this investigation the optimum ratio of the mass flow Ar/O2 was found to be about 1:1. Simultaneously, the RF power necessary for texture was found to be about 100W. The thickness, refractive index and extinction coefficient of LiNbO3 thin films were examined by ellipsometer. We have found the refractive index (n) is 2.2 (at 632.8nm), which is identical with the parameter of LiNbO3 ever reported. At the same time, the extinction coefficient of LiNbO3 thin films approachs to zero , represents that these thin films are suitable for optical waveguides.