HETEROEPITAXIAL GROWTH OF GROUP-IIa-FLUORIDE FILMS ON Si SUBSTRATES.

Growth conditions and structures of vacuum-evaporated heteroepitaxial CaF//2, SrF//2 and BaF//2 films on (111) and (100) oriented Si substrates have been investigated. Single crystal CaF//2 films are grown on both Si(111) and (100) oriented Si substrates have been investigated. Single crystal CaF//2 films are grown on both Si(111) and (100) substrates at temperatures of 600-800 degree C and 500-600 degree C, respectively. CaF//2 films on Si(111) have crystal orientations rotated 180 degree about the normal to the substrate surface. SrF//2 and BaF//2 films of good crystalline quality are grown on Si(111) at temperatures around 600 degree C, but are composed of two types of crystallites which have orientations either idential to those of the substrate or rotated 180 degree on the substrate surface about the surface normal. SrF//2 and BaF//2 films grown on Si(100) contain (111) oriented crystallites, and, in an extreme case, completely (111) oriented BaF//2 films were grown on Si(100).