Stannic-oxide films have the most excellent characteristics among electrically conducting and optically transparent films of metal oxides, and have been formed by chemical reaction of stannic-chloride or reactive sputtering of tin. We could obtain the transparent conducting stannic-oxide films of low resistance by vacuum evaporation.
Stannic-oxide powder in an alumina crucible was sublimated onto glass plates at 400°C by the radiation from tungsten wire coated with alumina. The deposited films were of stannous-oxide and non-conductive, but changed into stannic-oxide films of low resistance, when baked in air for suitable time.
The baked films had specific resistance of 2 × 10
-3Ω-cm, temperature coefficient of resistance of about - 0.05%/°C, stability of resistance at 200°C and transmittance at normal incidence of 85% in visible region. The conductivity depended on the reflectance of the stannous-oxide films before baking, then high conducting films could not be made from the deposited films of low reflectance. This vacuum-evaporation method, having the advantage of other's on several points, will be useful for production of the transparent conducting films of stannic-oxide used for special aims.
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