DEVELOPMENT OF THERMAL EXPANSION MEASUREMENT SYSTEM FOR CERAMIC THIN FILM

陶瓷薄膜在光学材料和电子材料方面的应用前景广阔。在这两种用途中，当陶瓷薄膜用于较高和较低的温度或腐蚀性气氛下时，有很多机会。因此，除了提高薄膜的力学性能外，衬底与薄膜之间的热膨胀系数的匹配成为一个重要的问题，它会影响衬底与薄膜之间的附着力和薄膜中的应力分布。本研究的目的是开发薄膜粘接在衬底上的热膨胀测量系统。为了得到薄膜的热膨胀系数，利用激光干涉仪测量了放置在电炉中的薄膜-衬底复合材料的曲线曲率半径的温度变化。在硅玻璃衬底上溅射非晶硅薄膜，对测量系统的有效性进行了检验。此外，我们还报道了利用该测量系统在硅玻璃衬底上获得的厚度约为1 μ m的溅射无定形氧化铝薄膜的热膨胀系数值。

Ceramic thin film is expected to be used increasingly in future as optical materials as well as electronic materials. In both uses, there are many opportunities when ceramic thin film is used for at a higher and a lower temperatures or under corrosive atmosphere. Accordingly, in addition to improvement of mechanical properties of the film, matching of the thermal expansion coefficient between a substrate and a film which gives influence to adhesion forces between them and stress distribution in the film becomes an important problem. A aim of this study is the development of the thermal expansion measurement system for the thin film which sticks to a substrate. In order to obtain thermal expansion coefficient of the film, the temperature change of radius of curvature of curve of the film-substrate composite placed in an electric furnace was measured by means of laser interferometer. Availability of the measurement system was examined using sputtered amorphous silica thin film on the silica glass substrate. Furthermore, we reported the value of thermal expansion coefficient of sputtered amorphous alumina film of about 1 mum thickness on silica glass substrate obtained using this newly-constructed measurement system.