The resistance temperature stability of ITO film strain gauge: detailed investigate the influence mechanism of (100) preferred orientation of ITO film

Abstract

The indium tin oxide (ITO) film is one of the ideal candidates for optical transparent film strain gauge. Thus, the temperature stability of electrical properties is most important for ITO film strain gauge. In this work, the film strain gauge consisted of polycrystalline ITO film with and without (100) preferred orientation. Total 25 temperature circles in range of 20–200–20 °C were carried out on ITO film and ITO film strain gauge. After 25 temperature circles, the carrier concentration and carrier mobility of polycrystalline ITO film without preferred orientation decreased (38.1 ± 1.7)% and (15.4 ± 3.3)%, respectively. Then, the resistivity of polycrystalline ITO film without preferred orientation increased (90.7 ± 6.4)% after 25 temperature circles. As result, the resistance of film strain gauge monotonously increased with the increase of temperature circles, which consisted of the polycrystalline ITO film without preferred orientation. On the contrary, the carrier mobility and carrier concentration of polycrystalline ITO film with (100) preferred orientation was fixed at the constant after each temperature circle. Similarly, the resistivity of ITO film and the resistance of ITO restrain gauge was fixed at the constant after each temperature circle, which consisted of the polycrystalline ITO film with (100) preferred orientation. Finally, based on the theories of film growth and crystallography, the relationship between resistance temperature stability of ITO film strain gauge and (100) preferred orientation, as well as the physicochemical mechanism behind them, were systematically investigated. With above results, ITO film with (100) preferred orientation could be an ideal candidate for optical transparent film strain gauge, especially for film strain gauge worked at variable temperature condition.