Abstract We report low optical loss germanium oxide (GeO2) thin films which have been deposited by low pressure ion-assisted alternating current dual magnetron sputtering of germanium targets in an oxygen plasma environment. The germanium oxide films ranging from 0.7- to 1.0-µm-thick were fabricated at low temperature and high deposition rates of 6–38 nm/min on silicon and thermally oxidized silicon substrates. The refractive index of the films was determined through variable angle spectroscopic ellipsometry and found to be 1.6051 on average at a wavelength of 638 nm. The films were shown to be near stoichiometric through Rutherford backscattering spectroscopy analysis and displayed sub-nanometer roughness when measured with atomic force microscopy. High peak-to-valley uniformity on a 3-inch substrate with relative deviation of 0.8% was achieved. We characterized the attenuation of the GeO2 thin films from visible to near-infrared wavelengths and observed it to be as low as 0.1 dB/cm at 638 nm for deposition rates of 8 nm/min. This deposition technique provides complementary metal-oxide-semiconductor compatible GeO2 thin films suitable for integrated photonics applications and is promising for the fabrication of other dielectric waveguide materials.

中文翻译：

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用于波导应用的离子辅助交流反应溅射沉积的低损耗 GeO2 薄膜

摘要 我们报告了低光学损耗氧化锗 (GeO2) 薄膜，该薄膜已在氧等离子体环境中通过锗靶的低压离子辅助交流双磁控溅射沉积。厚度为 0.7 到 1.0 µm 的氧化锗薄膜是在低温和 6–38 nm/min 的高沉积速率下在硅和热氧化硅衬底上制造的。薄膜的折射率通过可变角度光谱椭偏法测定，发现在 638 nm 波长下平均为 1.6051。通过卢瑟福背散射光谱分析显示薄膜接近化学计量，并且当用原子力显微镜测量时显示出亚纳米粗糙度。在 3 英寸基板上实现了高峰谷均匀性，相对偏差为 0.8%。我们表征了 GeO2 薄膜从可见光到近红外波长的衰减，并观察到它在 638 nm 处对于 8 nm/min 的沉积速率低至 0.1 dB/cm。这种沉积技术提供了适用于集成光子学应用的互补金属氧化物半导体兼容的 GeO2 薄膜，并有望用于制造其他介电波导材料。