采用反应电子束蒸发技术在不同氧分压下制备了HfO2薄膜,并采用X射线衍射仪、扫描电子显微镜、椭圆偏振仪、X射线光电子能谱仪、1064 nm弱吸收测试仪、1064 nm激光1-on-1损伤测试系统等,对HfO2薄膜的结构、光学性能、化学组分、吸收性能、抗激光损伤特性和损伤形貌等进行了表征和分析。当沉积温度为200 ℃时,所制备的HfO2薄膜为单斜多晶结构,晶粒尺寸约为10 nm。随着氧分压升高,薄膜的氧化程度随之增大,由化学计量比缺陷主导的薄膜1064 nm弱吸收系数变小,同时薄膜结构变得疏松,折射率随之降低。深入研究后发现,在采用反应电子束蒸发技术制备HfO2薄膜时,提高氧分压有助于抑制膜内纳米吸收缺陷和基底亚表面裂纹,提高HfO2薄膜抗1064 nm激光损伤阈值,对制备出基于HfO2薄膜的高性能光学元器件具有重要的参考价值。

In this study, HfO2 films were deposited by the reactive electron beam evaporation technique at different oxygen partial pressures. The corresponding properties of the film such as its structure, optical property, chemical composition, absorptive property, laser damage resistance, and damage morphology are characterized and analyzed using an X-ray diffractometer, a scanning electron microscope, an ellipsometer, an X-ray photoelectron spectroscopy, a 1064-nm weak absorptivity tester, and a 1064-nm 1-on-1 damage test system. At a deposition temperature of 200 ℃, the deposited HfO2 films show a monoclinic polycrystalline structure with a grain size of approximately 10 nm. As the oxygen partial pressure increases, the oxidation degree of the films increases, thereby reducing their 1064-nm weak absorptive coefficients, which are dominated by non-stoichiometric defects. Moreover, the structure of the films becomes looser and the refractive index decreases. This study suggests that increasing the oxygen partial pressure, during the HfO2 film deposition process using reactive electron beam evaporation, can promote the suppression of nano-absorption defects in the film and subsurface cracks in the substrate, and can increase the laser damage threshold, thereby providing an important reference for preparing high performance HfO2-based optical components.