Optical refractive index and static permittivity of mixed Zr–Si oxide thin films prepared by ion beam induced CVD

Mixed oxides ZrxSi1−xO2 (0 < x < 1) thin films have been prepared at room temperature by decomposition of (CH3CH2O)3SiH and Zr[OC(CH3)3]4 volatile precursors induced by mixtures of O2+ and Ar+ ions. The films were flat and amorphous independently of the Si/Zr ratio and did not present phase segregation of the pure single oxides (SiO2 and ZrO2). A 10–23 at.% of H and 1–5 at.% of C atoms remained incorporated in the films depending on the mixture ratio of the Si and Zr precursors and the composition of the bombarding gas used during the deposition process. These impurities are mainly forming hydroxyl and carboxylic groups. Optical refractive index and static permittivity of the films were determined by reflection NIR-Vis spectroscopy and C–V electrical characterization, respectively. It is found that the refractive index increases non-linearly from 1.45 to 2.10 as the Zr content in the thin films increases. The static permittivity also increases non-linearly from ∼ 4 for pure SiO2 to ∼ 15 for pure ZrO2. Optical and electrical characteristics of the films are justified by their impurity content and the available theories.