Characterization of low pressure annealed ITO/Au/ITO films prepared by reactive magnetron sputtering

Abstract

Abstract Transparent Sn-doped In 2 O 3 (ITO) single-layer and ITO/Au/ITO multilayer films were deposited on glass substrate by reactive magnetron sputtering to compare morphology, optical and electrical properties of the films and were then annealed in a vacuum of 1 × 10 −2 Pa at various temperatures from 150 to 450 °C to determine the influence of annealing temperature on the properties of the films. As-deposited 100 nm thick ITO films exhibit a sheet resistance of 130 Ω/□ and optical transmittance of 77% at 550 nm-wavelength. By inserting a 5 nm-thick Au layer in ITO/metal/ITO films, the sheet resistance decreased to as low as 21 Ω/□ and optical transmittance also decreased to as little as 73% at 550 nm-wavelength. Post-deposition annealing of ITO/Au/ITO films lead to considerably lower electrical resistivity, higher optical transparency, and crystallization of the films. A sheet resistance of 8 Ω/□ and an optical transmittance of 82% at 550 nm wavelength were obtained from the ITO/Au/ITO films annealed at 450 °C. In the X-ray diffraction pattern, as-deposited ITO films did not show any diffraction peak, while as-deposited ITO/Au/ITO films have Au (1 1 1) and In 2 O 3 (2 2 2) crystal planes. When the annealing temperature reached the 150–450 °C range, both diffraction peak intensities increased significantly.