Microstructure of Low-Resistivity Tin-Doped Indium Oxide Films Deposited at 150∼200°C

Abstract

Low-resistivity (∼2×10^-4 Ω· cm) tin-doped indium oxide (ITO) films were deposited at a relatively low substrate temperature (T _s) of 185° C by two representative low-temperature processes, i.e., dc magnetron sputtering using an oxide target and activated e-beam evaporation. Precise X-ray diffraction (XRD) measurements for both ITO films showed that all the XRD peaks split into two peaks with different intensity ratios depending on the deposition conditions and methods. The deconvolution analyses on the doublet XRD peaks and an investigation of the step-etched ITO films revealed that the films consisted of two differently strained layers. The weakly strained layer was consider to be formed as a result of crystallization of an as-deposited amorphous layer upon thermal annealing during deposition (solid-phase crystallization), whereas the strongly strained layer was an as-deposited crystalline layer (vapor-phase crystallization).