【課題】 感度が良好で、しかも、膜が剥離したりせ ず、基板の加工の容易な薄膜赤外線センサを提供するこ と。
【解決手段】 基板１の表面に強誘電体薄膜４を形成し てなる薄膜赤外線センサＳにおいて、前記基板１として シリコン基板を用い、このシリコン基板１と前記強誘電 体薄膜４との間に酸化アルミニウム薄膜２を形成してい る。
PROBLEM TO BE SOLVED: To obtain a thin-film infrared sensor whose sensitivity is good and whose silicon substrate can be worked easily by a method wherein an aluminum oxide thin film is formed between the silicon substrate and a ferroelectric thin film. SOLUTION: In order to reduce the heat capacity of a substrate 1, its rear surface side is etched. A substratum electrode 3 is composed of platimum. In addition, an upper-part electrode 5 is composed of chromium, and an infrared absorbing film 6 is composed of gold black. At this time, an aluminum oxide film 2 whose difference in a coefficient of thermal expansion from that of the substrate 1 is small and whose lattice constant is close to that of the substrate is formed on the substrate 1, and the thin film 2 acts as a buffer layer. Then, the electrode 3 on the thin film 2 and a ferroelectric thin film 4 can be epitaxially grown, the electrode 3 and the thin film 4 whose crystallinity is excellent can be formed, and the thin film 4 is not stripped from the substrate 1. Then, since the substrate 1 and the thin film 2 can be worked easily, a thin- film infrared sensor whose sensitivity is good can be mass-produced easily.