Characteristics of indium oxide films prepared by DC magnetron sputtering

Highly conductive transparent indium oxide (In₂O₃) thin films were prepared by DC magnetron sputtering using pure indium oxide targets. Sputtering was done in a pure Argon (Ar) atmosphere with a residual pressure of less than 4 × 10^-5 Torr. The substrate temperature was varied during the sputtering process from room temperature to 250°C. Some of the In₂O₃ samples were given a post-deposition heat treatment while still in vacuum. The indium oxide films were deposited on borosilicate glass plates 0.13÷0.17 mm thick and on optical slide glasses 1 mm thick. The resultants films were characterized for their optical, electrical and mechanical properties. Results show that films with resistivity as low as 2.7×10^-3 Ωcm, and transmittance as high as 92% in the visible range (400 ÷ 650 nm) can be obtained by gaining a complete control on the process parameters. A variance in the electrical, mechanical and optical properties of the In₂O₃ films was found in layers made on borosilicate glass substrates.