PRODUCTION OF THIN FERROELECTRIC FILM

摘要

PROBLEM TO BE SOLVED: To obtain a thin ferroelectric film with 001 axes oriented in a direction perpendicular to the surface of a substrate independently of the kind of the substrate by forming a buffer layer made of a specified thin perovskite film on the substrate and then bringing a thin ferroelectric film into crystal growth. SOLUTION: When a thin perovskite film is formed as a buffer layer on a substrate having 1.0×10<-5> -2.1×10<-5> / deg.C coefft. of linear thermal expansion, a thin oxide film having an amorphous structure and/or a pyrochlore structure as the crystal structure is formed in 0.05-0.3μm thickness on the substrate and the structure is turned into a perovskite structure by heating the film at 550-800 deg.C to form a buffer layer made of a thin perovskite film having 100 orientation at the Curie temp. or above on the substrate. The oxide is perovskite represented by the general formula ABO3 and the molar ratio of A to B is 0.8-1.2. A thin ferroelectric film having a perovskite structure and having tetragonal crystals at room temp. is then brought into epitaxial crystal growth on the thin perovskite film to form a perovskite structure having 001 orientation at room temp.