Abstract Er2O3 anti-reflection films were deposited on the surface of the chemical vapor deposited diamond films and Si(100) substrates by radio frequency magnetron sputtering. The microstructure of the Er2O3 thin films and the interfacial layer were investigated by means of scanning electron microscopy, X-ray diffraction, atomic force microscopy and transmission electron microscopy. The refractive index, hardness and transmittance of the films were measured by ellipsometry, nanoindentation measurements, and Fourier transformed infrared spectroscopy. Results revealed that the bias induces the formation of a monoclinic phase and the nucleation of the Er2O3 thin films is mainly observed along the (222) plane. A high-resolution TEM image revealed a 2.5-nm-thick amorphous layer at the interface between the Si substrate and Er2O3 film. Notably, monoclinic Er2O3 films can considerably improve the transmittance of the diamond film in the long-wavelength infrared range of 8–12 μm via the reduction of the refractive index. However, the introduction of the monoclinic phase led to the decrease of the hardness and elastic modulus of the films; hence, controlling a suitable amount of the monoclinic phase may play an extremely important role in the mechanical and optical properties of the Er2O3 films.

中文翻译：

---

射频磁控溅射沉积在金刚石涂层和 Si(100) 衬底上的 Er2O3 薄膜的显微结构、硬度和光学性能

摘要 采用射频磁控溅射在化学气相沉积金刚石薄膜和Si(100)衬底表面沉积Er2O3增透膜。通过扫描电子显微镜、X射线衍射、原子力显微镜和透射电子显微镜研究了Er2O3薄膜和界面层的微观结构。通过椭偏仪、纳米压痕测量和傅里叶变换红外光谱测量薄膜的折射率、硬度和透射率。结果表明，偏压诱导了单斜相的形成，并且 Er2O3 薄膜的成核主要沿（222）面观察到。高分辨率 TEM 图像显示在 Si 衬底和 Er2O3 膜之间的界面处有一个 2.5 nm 厚的非晶层。尤其，单斜晶 Er2O3 薄膜可以通过降低折射率来显着提高金刚石薄膜在 8-12 μm 长波长红外范围内的透射率。然而，单斜相的引入导致薄膜硬度和弹性模量的降低；因此，控制适量的单斜相可能对 Er2O3 薄膜的机械和光学性能起到极其重要的作用。