Influence of heat treatment on the structural, morphological and optical properties of DC magnetron sputtered Ti x Si1−x O2 films

Abstract

Ti x Si1−x O2 thin films were formed onto unheated p-silicon and quartz substrates by sputtering composite target of Ti80Si20 using reactive DC magnetron sputtering method. The as-deposited films were annealed in oxygen atmosphere at different temperatures in the range 400–900∘C. X-ray photoelectron spectroscopic indicated that the as-deposited films formed at oxygen flow rate of 8 sccm were of Ti0.7Si0.3O2. X-ray diffraction studies revealed that the as-deposited films were amorphous. The films annealed at 800∘C were exhibited broad (101) peak which indicated the growth of nanocrystalline with anatase phase of TiO2. The crystallite size of the films increased from 9 to 12 nm with increase of annealing temperature from 800 to 900∘C, respectively, due to increase in crystallinity and decrease in defect density. XPS spectra of annealed films showed the characteristic core level binding energies of the constituent Ti0.7Si0.3O2. Optical band gap decreased from 4.08 to 3.95 eV and the refractive index decreased from 2.11 to 2.08 in the as-deposited and the films annealed at 900∘C due to decrease in the lattice strain and dislocation density.