TiO2 Film Properties as a Function of Processing Temperature

TLDR: In this paper, annealing in air caused crystallization, with anatase formed beginning at 350°C and rutile at 700°C, while the density and index of refraction increased with increasing anneal temperature, while etch susceptibility in and decreased.

Abstract: Thin film was produced at 150°C by chemical vapor deposition using hydrolysis of tetraisopropyl titanate. Films were amorphous as grown, but annealing in air caused crystallization, with anatase formed beginning at 350°C and rutile at 700°C. Density and index of refraction increased substantially with increasing anneal temperature, while etch susceptibility in and decreased. Comparison with literature data showed two groups of processes. One group yields films having properties that gradually approach those of rutile with increasing process temperature. The other group gives rutile directly at moderate temperatures. Deposition of amorphous film, followed by etching and annealing is suggested as a means for pattern definition.