EFFECT OF ANNEALING ON ELECTRICAL AND OPTICAL-PROPERTIES OF RF MAGNETRON-SPUTTERED INDIUM TIN OXIDE-FILMS

Abstract

Indium tin oxide (ITO, 90wt%In2O3-10wt%SnO2) films of approximately mum thick have been deposited on glass substrates by radio-frequency (RF) magnetron sputtering. The effect of post-deposition heat treatment on the electrical and optical properties of ITO films are investigated. Annealing of ITO-coated substrates at a temperature of 350-550-degrees-C for 2 h in air causes the ITO layers to crystallize and grains to grow. Tin atoms are activated after annealing and behave as effective donors. The electrical resistivity of ITO film decreases by more than two orders of the magnitude after annealing. The infrared reflectance increases as the annealing temperature is raised. An infrared reflectance of approximately 60% (at 5 mum) is obtained for the 550-degrees-C-annealed sample. Several material parameters, such as the effective band gap and the refractive index, have been derived and discussed.