CHEMICAL VAPOR DEPOSITION OF THIN FILM MATERIALS FOR ...

e seen, the film grows with single orientation in the normal direction, since X-ray spectrum of
BTO film shows only reflections from (h00) crystallographic planes the same as those of MgO
substrate. According to this X-ray data, the out-of-plane lattice constant of BTO film is found to
be 4.007Å, which is a value between a and c lattice constants (a =3.992Å, c =4.032Å) of BTO
crystal at room temperature.[111] It’s impossible to identify the thin film growth in a or c
orientation based on this result. Moreover, the peak shift can be also attributed to the interfacial
stress. Out-of-plane and in plane texture of this sample are examined by ω and φ scan as shown
in Fig.58 (b) and (c). The measured FWHM (full-width-at-half-maximum) value of ω-scan of
BTO(200) is 0.5˚, which is about in the middle of those have been reported (0.23~0.9).
[117,130,138,139] The φ-scan of {101} planes of both BTO film and MgO substrate shows the
four coincidently 90˚ separated peaks. This result illustrated the four fold symmetry of both the
BTO and MgO lattice. Meanwhile, the coincidence of peaks positions indicate a cube on cube
epitaxial relationship.
Fig. 59. (a) Cross sectional view of BaTiO3 on MgO by SEM (b) Surface view of BaTiO3 film on MgO; inlet shows
a 10 μm by 10 μm AFM image of the same surface with RMS roughness around 20 nm.
Cross sectional and surface morphology of the as deposited BaTiO3 film on MgO has
been characterized by SEM and AFM. As seen in Fig. 59(a), the cross section of a ~0.5 μm thick
(1 hour deposition) BaTiO3 film on MgO substrate presents certain defects, especially at the
111