Formation and patterning of tin oxide transparent

氧化锡薄膜具有成本低、耐摩擦、耐化学腐蚀等优点，被广泛用于太阳能电池等透明电极。然而，氧化锡薄膜不能应用于液晶显示等，因为用酸化学蚀刻是不可能形成图案的。本课题的目的是建立一种新的氧化锡透明导电膜的生产工艺，特别是利用本课题研究人员首创的一种成膜技术，即碘化锡蒸发膜的光化学反应，实现氧化锡薄膜的图案形成。目前的项目是在两年内完成的。在第一年（1992年），对薄膜沉积的参数进行了实验优化；主要参数为蒸发源温度、薄膜厚度、衬底温度和真空压力。研究发现，精确控制蒸发源的温度对保持产品的重现性尤为重要。第二年（1993年），研究了不同条件下氧化锡的形成；主要实验参数为温度、光辐射、处理时间和大气。人们发现大气中氧气的存在决定了这一反应。加热和光辐射可以加速反应。本项目获得的新知识之一是碘化锡（IV） SnI_4作为中间化合物的检测，阐明了碘化锡（II） SnI_2与氧化锡的光化学反应，从而成功地建立了普遍的工业应用技术。

Tin oxide films are widely used for transparent electrode for solar Cells etc. because of the advantage of low cost, frictional and chemical dubrability. However, tin oxide films cannot be applied to liquid crystal display etc. since the pattern formation by chemical etching with acids is impossible. The object of the present project is establishemnt of a novel production process of tin oxide transparent conductive films, particularly achievement of pattern formation of tin oxide films by a film formation technology originated by the present investigators, i.e. photochemical reaction of tin iodide evaporated film.The present project was prosecuted in two years. In the first year, (1992's), the parameters for the film deposition were experimentally optimized ; the main parameters were, temperature of the evaporation source, film thickness, substrate temperature and vacuum pressure. Precise temperature controle of the evaporation source was found to be particularly important to maintain the reproducibility of the product. In the second year (1993's), formation of tin oxide was investigated under various cnditions ; the main experimental parameters were, temperature, radiation of light, treating time and atmosphre. The presence of oxygen in the atmosphere was found to govern the reaction. The heating and light radiation was found to accelerate the reaction.One of the new knowledges obtained through the present project was detection of tin iodide (IV) SnI_4 as an intermediate compound by which the photochemical reaction from tin iodide (II) SnI_2 to tin oxide was elucidated so that universal industrial application technology was successfully established in the present project.