Electrical and structural properties of low resistivity tin-doped indium oxide films

Abstract

Tin‐doped indium oxide (ITO) films with the resistivity less than 1.35×10−4 Ω cm were formed by low voltage dc magnetron sputtering (LVMS) and highly dense plasma‐assisted electron beam (EB) evaporation using the arc plasma generator (HDPE). The structural properties of these films were investigated using x‐ray diffraction, scanning electron microscope, and electron spectroscopy for chemical analysis, in comparison with the films formed by conventional magnetron sputtering and EB evaporation, in order to clarify the key factors for low resistivity. With decreasing plasma impedance and sputtering voltages from 540 to 380 V, the resistivity of the filmsdeposited at T s =400 °C decreased from 1.92 to 1.34×10−4 Ω cm, due mostly to increase in the carrier density. This LVMS film showed higher crystallinity because of lower damages of high‐energy particles during the deposition, which might increase the number of electrically active species. For HDPE, the film with resistance of 1.23×10−4 Ω cm was deposited at T s =280 °C, which showed more flat surface morphology and less surface segregation of tin than the conventional EB films.