Properties of ITO thin films prepared by APS-assisted EB evaporation

ITO thin films were prepared by oxygen ion-assisted electron beam (EB) evaporation technique onto K9 glass substrate at low temperature and effects of substrate temperature, oxygen flux on the structure, electrical and optical properties of ITO thin films were investigated. An advanced plasma source (APS) was used to produce high density argon and oxygen ion flux to cause electron degeneracy in the band gap by introducing non-stoichiometry in the ITO films to improve the conductivity of the prepared films. The structure of the ITO thin films were characterized by XRD and the results shown that all of the ITO films deposited at the temperature above 160°C shown a polycrystalline structure. And as the substrate temperature increased, the optical transmittance and electrical conductivity were improved. It is also found that the increase of oxygen flux increased the optical transmittance of the deposited ITO films, however, at a given deposition rate, the electrical conductivity showed a maximum in a certain range of oxygen flux. ITO thin films with the resistivity of 1.65×10-4 Ω· cm and an optical transmittance of above 90% in the visible region were prepared at a temperature of 250°C by the given method.