目的 研究不同晶体结构Y2O3薄膜的性质及其对金刚石增透性能的影响规律。方法 采用反应磁控溅射的方法，通过控制氧氩比，在金刚石膜上制备立方与单斜两种不同晶体结构的Y2O3薄膜，随后系统研究两种Y2O3薄膜的性质与增透性能。结果 在低氧氩比下获得了立方结构Y2O3薄膜，在高氧氩比下获得了单斜结构Y2O3薄膜，二者表面粗糙度分别为2.57、1.07 nm。两种晶体结构均呈现出符合Y2O3原子配比的价态。立方和单斜结构的Y2O3薄膜硬度分别为17.4、12.6 GPa；弹性模量分别为248.1、214.6 GPa。双面镀制立方结构Y2O3薄膜后，金刚石膜在10.0 μm透过率最大，达89.1%，增透24.5%；单斜结构Y2O3薄膜在7.4 μm透过率最大，达90.4%，增透25.4%。结论 通过控制氧氩比可以获得热力学稳定的立方Y2O3薄膜和亚稳态的单斜Y2O3薄膜。立方和单斜结构的Y2O3薄膜中O与Y原子价态均符合其化学计量比。立方结构Y2O3薄膜呈现出更高的硬度与弹性模量。两种结构对金刚石窗口均呈现出良好的增透效果。单斜结构Y2O3薄膜增透效果更佳与其较低的折射率有关，且相比于立方结构Y2O3薄膜，增透最佳值向低波长方向移动。

To investigate the properties of Y2O3 film with different crystal structures and the influence rules on the an-ti-reflection performance of diamond. Y2O3 films with cubic and monoclinic crystal structures were prepared by reactive magnetron sputtering on the diamond window by changing oxygen-argon ratio. Then, the properties and anti-reflection performance of two films were studied systematically. Y2O3 films with cubic structure were obtained at low oxygen argon ratio and monoclinic structure were obtained at high oxygen argon ratio. Surface roughness of the two films was 2.57 nm and 1.07 nm, respectively. Both crystal structures showed valence states according with atomic ratio of Y2O3. Hardness of two Y2O3 thin films with cubic and monoclinic structures was 17.4 GPa and 12.6 GPa, respectively. Elasticity modulus was 248.1 GPa and 214.6 GPa, respectively. The maximum transmittance of diamond film was 89.1%, and 24.5% of transmittance was obtained after the Y2O3 film with cubic structure was deposited on both sides of diamond. The maximum transmittance of diamond film was 90.4%, and 25.4% of transmittance was obtained after Y2O3 film with monoclinic structure was deposited on diamond. Thermodynamically stable cubic Y2O3 films and metastable monoclinic Y2O3 films can be obtained by controlling oxygen argon ratio. The valence states of O and Y in Y2O3 films with cubic and monoclinic structure are in accordance with their stoichiometric ratios. Y2O3 thin films with cubic structure exhibit higher hardness and elastic modulus. Both structures show good anti-reflection effect on diamond window. Compared with the monoclinic Y2O3 structure, the anti-reflection effect of Y2O3 thin film is better, which is related to the lower refractive index, and the optimal anti-reflection value of Y2O3 thin film with monoclinic structure moves towards the direction of low wavelength compared with the films with cubic structure.