Effect of sputtering power on the properties of SiO2 films grown by radio frequency magnetron sputtering at room temperature

SiO2 thin films were prepared with radio frequency magnetron sputtering on quartz glass substrates, and the effects of sputtering power on the stoichiometric ratio, microstructure, surface morphology and optical properties of the film within 300-1100 nm were investigated. The molar ratio of O/Si in the film increased continuously from 1.87 to 1.99, very close to the ideal stoichiometric ratio of 2:1 with the sputtering power decreasing from 150 to 60 W. And the surface of SiO2 thin film became more compact and flatter, and the roughness was significantly reduced. All the SiO2 films were amorphous, and the power had no obvious effect on the crystalline state of the film. When the sputtering power decreased from 150 to 60 W, the refractive index and absorptivity of SiO2 film in the range of 300-1100 nm decreased continuously, while the transmittance within 300-1100 nm of the coated quartz glass (hereinafter referred to as the transmittance of film) increased continuously, and the integrated transmittance increased from 92.7 to 93.0%.