X射线反射法和椭圆偏振法结合测量热处理溶胶-凝胶ZrO2薄膜的结构和光学参数

摘要

采用溶胶-凝胶法在硅片基底上制备ZrO2薄膜,在150℃～750℃范围内不同温度下进行热处理,研究了热处理对膜层结构和光学性能的影响.X射线反射用于膜层厚度和界面粗糙度分析,结果表明热处理温度由150℃升至750℃,膜层厚度由常温状态下的112.3nm减小到34.0nm,表面和界面粗糙度均小于2nm.以X射线反射法测得的膜层厚度为初始值,对椭圆偏振仪的测量结果进行拟合,得到不同温度的膜层折射率,结果表明热处理温度为550℃时膜层折射率达到最大值.X射线反射作为直接的膜层厚度测试手段,所得结果为准确分析椭偏光谱提供了参考.%ZrO2 thin films were first deposited by the sol-gel method on Si substrates and then heat-treated from 150℃ to 750℃. X-ray reflectivity and spectroscopic ellipsometry were employed to determine the structural and optical parameters of the films at different annealing temperatures. X-ray reflectivity accurately provided film thickness and interface roughness. The results indicate that, with increasing temperature from 150℃ to 750℃ , the films shrank from 112. 3 nm to 34. 0 nra and the surface roughness as well as the interface roughness was less than 2 nm. The film thickness from X-ray reflectivity was used as an initial value for the evaluation of the spectroscopic ellipsometry data to reveal the film refractive index as a function of temperature. Heat treatments from 150℃ to 750℃ result in first an continuous increase of refractive index from 1. 648 (at 633 nm) to 1. 955 and then a decrease to 1. 936 with the watershed temperature of 550℃. The combination of X-ray reflectivity and spectroscopic ellipsometry can improve the reliability of optical characterization for optical films.