Heteroepitaxial growth of TiO2 films by ion-beam sputter deposition

Heteroepitaxial TiO2 films of the rutile and anatase phases have been grown using the ion-beam sputter deposition technique. The orientations of the highest-quality rutile films grown and their corresponding substrates are (100)/(0001)Al2O3, (101)/(<11(2)over bar 0>)Al2O3, (001)/(<10(1)over bar 0>)Al2O3, and (110)/(110)MgO. This is the first report of the heteroepitaxial growth of (001)/(<10(1)over bar 0>)Al2O3 and (110)/(110)MgO rutile films. Results indicate that the films are aligned both perpendicular and parallel to the plane of the film. Distinct surface morphologies are observed for each orientation. The (100) and (101) rutile orientations were also grown on (111)MgO and (<1(1)over bar 02>)Al2O3, respectively. The (100) anatase grew on both (100)MgO and MgAl2O4. The growth mechanisms of several rutile films on Al2O3 substrates were investigated, and the data suggest island or Volmer-Weber type growth.