采用射频反应磁控溅射方法在硅衬底制备了HfSixOy薄膜，用X射线光电子能谱(XPS)分析了HfSixOy薄膜的成分，用X射线衍射(XRD)检测了薄膜的结构, 并用椭圆偏振光谱仪研究了退火处理对薄膜光学性质的影响。XRD谱显示,HfSixOy薄膜经700 ℃高温退火处理后仍为非晶态，而在900 ℃高温退火处理后出现晶化。采用Tauc-Lorentz (TL)色散模型对测试得到的曲线进行拟合并分析得出薄膜的光学常数，结果表明，薄膜的折射率随退火温度的升高而增加，而消光系数随退火温度的升高呈降低趋势。薄膜的光学带隙随着退火温度的升高增加，采用外推法得到薄膜沉积态和经500 ℃，700 ℃，900 ℃退火后的带隙分别为5.62，5.65，5.68，5.98 eV。

HfSixOy thin films are prepared by using radio-frequency (RF) magnetron sputtering on p-type Si(100) and then annealed in N2 atmosphere. Composition and structure of the films are determined by means of XPS and XRD, respectively. The optical properties in relation to postdeposition annealing temperatures are investigated by spectroscopic ellipsometry(SE). The XRD analysis shows that the films are amorphous even after annealed at 700 ℃ but crystallization after annealed at 900 ℃. Based on a parameterized Tauc-Lorentz dispersion model, the optical constants of the as-deposited and annealed films related to the annealing temperature are systematically extracted. With the increase of the annealing temperature, the refractive index n of the HfSixOy films increases whereas the extinction coefficient k of the HfSixOy films decreases. The extracted direct band gaps are 5.62, 5.65, 5.68 and 5.98 eV for the as-deposited films and the films annealed at 500 ℃, 700 ℃ and 900 ℃, respectively.