衬底温度对HfO_2薄膜结构和光学性能的影响

Influence of substrate temperature on structural and optical properties of HfO_2 thin films

采用直流磁控反应溅射法,分别在室温,200,300,400和500℃下制备了HfO2薄膜。利用X射线衍射(XRD)、椭圆偏振光谱(SE)和紫外可见光谱(UVvis)研究了衬底温度对HfO2薄膜的晶体结构和光学性能的影响。XRD研究结果显示:不同衬底温度下制备的HfO2薄膜均为单斜多晶结构;随衬底温度的升高,(-111)面择优生长更加明显,薄膜中晶粒尺寸增大。SE和UVvis研究结果表明:随衬底温度升高,薄膜折射率增加,光学带隙变小;制备的HfO2薄膜在250～850nm范围内有良好的透过性能,透过率在80%以上。

HfO2 films were deposited by direct current reactive magnetron sputtering on n-type Si（100） substrates and fused silica substrates, respectively. The substrate temperature ranges from room temperature to 500 ℃. The influence of substrate temperature on structure and optical properties of the films was investigated by X-ray diffraction（XRD）, spectroscopic ellipsometry（SE） and ultraviolet visible spectroscopy（UV-vis）. XRD results show that all deposited films are polycrystalline with monoclinic structure. As the substrate temperature increases, the preferred orientation of （-111） becomes more obvious, and the grain size of HfO2 films increases. SE and UV-vis results demonstrate that, with the substrate temperature increasing, the refractive index increases and the optical band gap decreases. An excellent transmittance, exceeding 80% in the range from 250 nm to 850 nm, is obtained for all samples.