A STUDY OF THE OPTICAL, ELECTRICAL AND STRUCTURAL-PROPERTIES OF REACTIVELY SPUTTERED INOX AND ITOX FILMS

Films of InOx and ITOx were prepared by DC reactive sputtering from in dium and indium-tin alloy targets, respectively, in an oxygen/argon at mosphere. The compositions of the InOx films, determined from EDX, hav e been used to show how x varies as a function of O-2 partial pressure in the flow to the sputtering system. Reflectance and transmittance o f the InOx films and ITOx films were measured in the photon energy ran ge 0.5-6.0 eV, leading to determination of absorption coefficients as a function of x. The optical band gap, which appears as x is increased , was found to increase monotonically with x. The DC resistivity of In Ox films has been determined as a function of composition, as have the refractive indices for transparent films and thickness of all InOx an d ITOx films. The local structure of InOx and ITOx samples is shown by extended X-ray absorption fine structure to have much configurational disorder throughout the composition range. (C) 1997 Elsevier Science S.A.