EFFECT OF BIAS AND POSTDEPOSITION VACUUM ANNEALING ON STRUCTURE AND TRANSMITTANCE OF ITO FILMS

Indium tin oxide (ITO) films have been deposited on K(g) glass substrates by dc magnetron triode reactive sputtering under a bias voltage. The cathode target (83 wt% In+17 wt% Sn, diameter D = 160 mm, thickness h = 3 mm) was sputtered in an Ar+O2 gas mixture at a total pressure of 0.1 Pa (the oxygen partial pressure was 8x10(-3) Pa, P(O2)/P(Ar) = 2/23). The temperature and time of post-deposition annealing were between 350 and 500-degrees-C for 40 min in vacuum at 5x10(-4) Pa. The bias voltage and annealing resulted in In2O3 growth along the (222) crystal plane orientation in the ITO film. The bias voltage also can affect the optical properties of the ITO film. After bias voltage treatment and vacuum annealing an ITO film was obtained with a resistivity of about 3 x 10-4 OMEGA . cm and transmittance better than 85% in the visible spectrum.