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A comparative study was performed to investigate how etching methods and parameters affect the properties of ${{\rm SiO}_2}$SiO_2 and ${{\rm HfO}_2}$HfO_2 coatings. ${{\rm SiO}_2}$SiO_2 and ${{\rm HfO}_2}$HfO_2 single layers were prepared by electron-beam evaporation (EBE), ion-beam assisted deposition (IAD), and ion-beam sputtering (IBS). Then, ion-beam etching (IBE), reactive ion etching (RIE), and inductively coupled plasma etching (ICPE) were used to study the influence of ion bombardment energy and chemical reaction on the etching rates and properties of the prepared ${{\rm SiO}_2}$SiO_2 and ${{\rm HfO}_2}$HfO_2 single layers. For ${{\rm SiO}_2}$SiO_2 coatings, chemical reaction plays a dominant role in determining the etching rates, so ICPE that has the strongest ${{\rm CHF}_3}$CHF_3 plasma shows the highest etching rate. Moreover, all three etching methods have barely any influence on the properties of ${{\rm SiO}_2}$SiO_2 coatings. For ${{\rm HfO}_2}$HfO_2 coatings, the etching rates are more dependent on the ion bombardment energy, although the chemical reaction using ${{\rm CHF}_3}$CHF_3 plasma also helps to increase the etching rates to some extent. To our surprise, the ion bombardment with energy as high as 900 V does not change the amorphous microstructure or crystalline states of prepared ${{\rm HfO}_2}$HfO_2 coatings. However, the high-energy ion bombardment in IBE significantly increases the absorption of the ${{\rm HfO}_2}$HfO_2 coatings prepared by all deposition techniques and decreases their laser damage resistance to different extents.

SiO_2 films were deposited on fused silica, silicon, glass, germanium, and sapphire substrates by an ion beam sputtering technique. The optical properties of SiO_2 films on different substrates and interfacial layer properties between SiO_2 films and different substrates were researched by the spectroscopic ellipsometry technique. The refractive indices of SiO_2 films deposited on different substrates are about 1.477 at the wavelength of 632.8 nm. The optical anisotropy property of SiO_2 films on fused silica substrate is the best. The impact of thermal treatment on surface roughness and interfacial layer properties between SiO_2 films and Si substrates were also investigated. When the annealing temperature is 550°C, the least surface thickness and thinnest interface layer thickness between SiO_2 films and silicon substrate can be achieved. The results indicate that the surface and interface layer properties between SiO_2 films and silicon substrate can be greatly improved when the optimum annealing temperature is selected.

Effects of ion energy on the optical, microstructure, and electrical properties of Ge films prepared by ion-beam-assisted deposition were investigated. The absorption edge is found to shift toward a longer wavelength when the ion energy increases. 150 eV ion bombardment energy could help to reduce absorption in the infrared spectrum, elevating 2% of film transmittance. Diffraction intensity decreases with bombardment ion energy indicates that the crystallinity of Ge film is degenerated. Electrical property has been analyzed through Hall measurement. The resistivity of sample prepared with 300 eV ion energy drops substantially from 477 to 137 Ω cm, and it changes slowly with further increase of ion bombardment energy.