Preparation of Epitaxial BaTiO3 Thin Films by Plasma-Enhanced Metalorganic Chemical Vapor Deposition (Pe-Mocvd)

The plasma-enhanced metalorganic chemical vapor deposition (PE-MOCVD) process has been successfully used to achieve high quality epitaxial growth of BaTiO3 thin films on (001) LaA103 and (001) NdGaO3 substrates at a substrate temperature of 680°C. The PEMOCVD system, which incorporates a 300-Watt microwave cavity, introduces excited species from an oxygen plasma to lower the required deposition temperature, as compared to thermal MOCVD growth of BaTiO3. X-ray diffraction (XRD) θ-20 scan patterns indicate that there are few randomly oriented grains and impurity phases in the epitaxial BaTiO3 films. Results of XRD ϕ-scans of the BaTiO3 (202) reflection show a modulation pattern of peaks every 90°, which demonstrates that the BaTiO3 thin films have no misorientation along the [100] and [010] directions of the substrates. An XRD ω rocking curve of the BaTiO3 (200) reflection had a narrow FWHM of 0.25°, indicating that the films have a high degree of preferred orientation of <100> perpendicular to the substrates. The high degree of epitaxial crystallinity is further confirmed by Rutherford Backscattering Spectrometry which gives a minimum yield of 7.5% and 11% for the films deposited on LaAIO3 and NdGaO3, respectively. Scanning electron micrographs show that these films have very smooth surface morphologies, which are desirable for device applications.