EPITAXIAL-GROWTH OF TIO2 RUTILE THIN-FILMS ON SAPPHIRE SUBSTRATES BY A REACTIVE IONIZED CLUSTER BEAM METHOD

TiO2 thin films were grown on sapphire substrates at 500-degrees-C by means of reactive ionized cluster beam (RICB) deposition. The TiO2 thin films grown on sapphire (0001) and (1120BAR) substrates were single-crystalline and had the rutile structure. The epitaxial orientation relationships between the rutile films and the sapphire substrates were found to be (1) rutile (200)//Al2O3(0001) and (2) rutile (101)//Al2O3(1120BAR). On (1102BAR) sapphire substrates, the films showed both the anatase (101) and rutile (101) structures. The concept of near-coincidence lattice sites was applied to show that the lattice misfit at the interface between these rutile and sapphire planes was small (less than a few percent).