Epitaxial Bi4Ti3O12 thin film growth using Bi self-limiting function

Epitaxial Bi4Ti3O12 (BIT) thin films are grown by molecular beam epitaxy using the Bi self-limiting function. On appropriate growth conditions, Bi and Ti atoms are supplied with a large Bi/Ti supply ratio. The deficiency of Bi composition in the growing film is prevented by this large ratio, and surplus Bi atoms which do not contribute to BIT growth are evaporated from the surface. BIT films are characterized by reflection high-energy electron diffraction, atomic force microscopy, and X-ray diffraction. The films grow in a two-dimensional layer-by-layer manner whose layer unit is the 1.6 nm thick BIT molecular layer. As a natural consequence of the method, the thickness of BIT films is determined simply by the total amount of Ti atom flux. (C) 1999 Elsevier Science B.V. All rights reserved.