DEVELOPMENT OF THERMAL EXPANSION MEASUREMENT SYSTEM FOR CERAMIC THIN FILM

陶瓷薄膜作为光学材料和电子材料具有广阔的应用前景。在这两种用途中，当陶瓷薄膜在较高和较低温度下或在腐蚀性气氛下使用时，存在许多机会。因此，除了膜的机械性能的改善之外，基板和膜之间的热膨胀系数的匹配成为重要的问题，该热膨胀系数对它们之间的粘附力和膜中的应力分布产生影响。本研究的目的之一是发展一套薄膜热膨胀量测系统，用以量测贴附于基板上的薄膜热膨胀。为了获得薄膜的热膨胀系数，采用激光干涉仪测量了置于电炉中的薄膜-基体复合材料的曲率半径随温度的变化。测量系统的可用性进行了检查，使用溅射的无定形二氧化硅薄膜上的二氧化硅玻璃基板。此外，我们还报道了使用这种新构建的测量系统获得的二氧化硅玻璃衬底上溅射的厚度约为1 μ m的非晶氧化铝膜的热膨胀系数值。

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.