Physical Properties and Structure of Rf‐Sputtered Amorphous Films in the System Ti0 ₂ ‐Si0 ₂

Abstract

Amorphous films in the system Ti0 2 ‐Si0 2 were prepared by rf sputtering and their density, refractive index, and thermal expansion were measured. Also, the silicon Kα and titanium Kβ band emission spectra were obtained by X‐ray emission spectroscopy in order to determine the coordination state of silicon and titanium ions in these amorphous films. The density and refractive index increased, but not proportionally, with increasing Ti0 2 content. On the other hand, a minimum was observed in the thermal expansion coefficient at =15 mol% Ti0 2 . The coordination state of silicon ions in the amorphous films did not change with Ti0 2 content. However, the coordination number of titanium ions changed from 4 to 6, depending on Ti0 2 content. These results indicate that, in amorphous films in the system Ti0 2 ‐Si0 2 , the change of the coordination state of titanium ions has an important effect on physical properties, such as volume, molar refractivity, and thermal expansion.