Aerosol-Assisted Chemical Vapor Deposition of Transparent Conductive Gallium-Indium-Oxide Films

Aerosol assisted chemical vapor deposition (AACVD) reactions of GaMe3, InMe3, and 6 equiv of the donor fiinctionalized alcohol, HOCH2CH2OMe, in toluene resulted in the deposition of colorless, transparent gallium indium oxide films at a range of temperatures (350-450 degrees C). The gallium indium oxide films were analyzed by a range of techniques including scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), glancing-angle X-ray powder diffraction (XRD), and wavelength dispersive analysis of X-rays (WDX). The optimum growth temperature was found to be 450 degrees C, which produced transparent films with a composition of Ga0.6In1.4O3 as determined by WDX. XPS confirmed the presence of indium, gallium, and oxygen in the films. Annealing these films at 1000 degrees C resulted in crystalline films, and glancing-angle powder XRD showed a gallium-substituted cubic In2O3 lattice was adopted with a lattice parameter, a = 9.84 angstrom. AFM showed that the annealed films on quartz had a root-mean-square roughness of 94-200 nm, and the work function was measured to be 4.6 eV. The four point probe method was used to determine a sheet resistivity, R-s = 83.3 Omega/square, and a low electrical resistivity value (for example 6.66 x 10(-4) Omega cm in 80 nm sample thickness, as determined by side-on SEM for films deposited on glass).