Preparation and Characterization of ITO Thin Films Deposition by Ion Beam Assisted Deposition

Indium Tin Oxide (ITO) thin films are prepared by ion-beam assisted deposition at room temperature. An assisting oxygen ion beam (ion energy Ei=0 eV-600 eV) directly bombards the substrate surface to modify the properties of the ITO thin films. The effects of assisting ion beam energy on the characteristics of ITO thin films were investigated based on transmission scanning electron microscopy and atomic force microscopy. With an increasing assisting ion beam bombardment, the crystalline quality of the ITO films was improved and the oxygen vacancies were increased. SEM measurements showed that the film deposited at 300 eV had the characteristics of polycrystalline thin films with a larger grain structure than that of other conditions. The XRD spectra indicated that the ITO films that were produced in this study had polycrystalline structures. That means that surface ad atoms had enough mobility to migrate on the substrate with transferred kinetic energy by colliding secondary ions. However, too energetic secondary ion beam bombardments decreased grain size and also roughened surface morphology due to radiation damage. Optical transmittance of the ITO film in the visible region was related to the structural and surface morphological properties. In this study, the highest optical transmittance of 85% at a wavelength of 550 nm and the lowest resistivity of 3 x 10(-4) cm were obtained at the oxygen Ion Beam Energy 300 eV, respectively.