SPRAY-PYROLYSIS DEPOSITION FOR INDIUM OXIDE DOPED WITH DIFFERENT IMPURITIES

Spray pyrolysis including the doping process of impurities of different valence for preparation of transparent conductive indium oxide thin films is investigated. In this work, the oxidized Si wafers and pyrex glass slides are used as substrates. Low concentration InCl3,-methanol solution is the main source chemical with ZnCl2, SbCl3 and TeCl4 as additives for dopants. The deposition process and Nm properties are characterized as functions of various process parameters including the substrate temperature, the now rate and the concentrations of reactants. In general, the deposition rates are optimized to reach 40 to 50 nm/min at substrate temperatures between 300 degrees C and 325 degrees C. All the films are smooth and transparent in the visible and IR range of radiation with transparency greater than 90%. The refractive index is between 1.8 and 2.1. The resistivity of the In2O3 films without doping is in the range of 2 x 10(-3) to 8 x 10(-3) Omega-cm. It increases with Zn doping by an order of magnitude while decreases with Sb and Te as dopants. In this work, the lowest resistivity from Te doping reaches to 5 x 10(-4) Omega-cm.