電子シャワー法によるITO薄膜の作製とNO₂検知特性の評価

抄録

When indium tin oxide (ITO) film was prepared using an electron shower, it was found that ITO whiskers grew due to the vapor-liquid-solid (VLS) mechanism. The whisker radius was 10nm and the length 600nm. To grow whiskers, the substrate temperature should be above 200°C and the deposition rate above 6Å/s. Two types of whiskers grew: (a) those grown along the substrate during early growth (t≤30s), and (b) those grown vertical to the substrate at t≥30s.
ITO film consisting of (a) whiskers showed high gas-sensing characteristic for NO₂ at 200°C. Its sensitivity for 500ppm NO₂ was 10 times higher than that of other films consisting of (b) whiskers or plate-like crystals, for example. This shows that ITO film prepared using an electron shower is a potential candidate for semiconductor sensor elements.