Room Temperature Growth of Indium Oxide Films by Reactive Ion Beam Assisted Deposition

Abstract

AbstractConducting and semiconducting indium oxide thin films have been grown at room temperature by oxygen ion beam assisted e-beam evaporation. We studied an influence of the deposition conditions on thin film properties including the crystal structure, resistivity, optical transmittance, stoichiometry, morphology, and intrinsic stress. X-ray diffraction analysis shows that the crystal structure of indium oxide films changes from amorphous to polycrystalline with preferred (222) orientation when the discharge current increases from 0.5 A to 2.0 A. Film resistivity is tailored in a wide range from 3E-4 ohm-cm to 2E9 ohm-cm by modifying both the evaporation rate of indium and the discharge current of the oxygen ion source. X-ray photoelectron spectroscopy data reveal that the highly-resistive films are more oxygen-enriched than the highly-conductive samples due to electrical activity of the oxygen vacancies. Morphological properties are evaluated using an optical profiler and a measured root-mean-square (RMS) roughness is ~1 nm for produced indium oxide films. All films being studied in this work have compressive stress ranging from 0.4 Gpa to 1.8 Gpa. They are highly transparent with a transmittance up to 90%.Thus, high-performance indium oxide films can be engineered by the reactive ion beam assisted deposition to meet the requirements of different applications such as solar cells, photodetectors, OLEDs, transparent TFTs, and optical coatings.