Formation of Epitaxial Soi Structures Using Alkaline Earth Fltuoride Films

ABSTRACTRecent progress in the research of heteroepitaxial SOI structures such as Si/CaF2/Si and Ge/CaF2/Si structures is reviewed. Structural and electrical properties of alkaline earth fluoride films on Si substrates are first discussed. Growth conditions, structural properties, and device applications of the Si/CaF2/Si structures are then presented. It is shown that a predeposition technique, in which a thin Si layer is deposited at room temperature prior to the growth of a thick film at elevated temperature, is effective to improve the crystalline quality and the surface morphology of the film. Usefulness of solid phase epitaxy to obtain high quality films is also demonstrated. Finally, it is shown that the predeposition technique is also useful in formation of Ge/CaF2/Si structures.