Devitrification of Tin Oxide Films (Doped and Undoped) Prepared by Reactive Sputtering

Abstract

Tin oxide films doped with antimony oxide formed by reactive sputtering of tin‐antimony alloy cathodes can be made conductive at room temperature by heating in air at elevated temperatures (ca. 710°C) if the atom per cent of antimony in the cathode is between 3.0 and 14%. The kinetics is quite complicated with room temperature resistance of quenched samples showing two minima as a function of time of heating. The kinetics is speeded up if carbon is applied to the sputtered film prior to firing. This treatment introduces oxygen vacancies and allows even indium doped films to be made conductive on firing. For 3500Aå thick films of antimony doped tin oxide the highest conductivity obtained is 175 ohms □−1. The temperature coefficient of resistivity ranges from negative to +2000 ppm/°C, depending on composition.