Effect of deposition parameters on the microstructure of chemically vapour-deposited SnO 2 films

Abstract

Transparent electrically conducting tin oxide films were deposited onto Pyrex glass substrates by oxidation of SnCl 2. The deposition temperature was in the range 400–500°C and oxygen with a flow rate of 1.35–2.50 1 min -1 was used as both the carrier gas and the oxidizing agent. Scanning electron microscope studies of these films indicate that the mean grain size varies from 0.083 to 0.303 μm. It was found that the film uniformity and the mean grain size increase with increasing deposition temperature and decreasing oxygen flow rate. This behaviour is explained in terms of the deposition rate, surface mobility and grain growth rate. SnO 2 films deposited at a high temperature (500°C) with a low oxygen flow rate (1.35 1 min -1) are uniform with a large mean grain size (0.303 μm). Doping SnO 2 films with antimony to 4 mol.% does not affect the film microstructure.