Integration of complex oxides, such as barium ferrite [BaFe₁₂O₁₉] and lead zirconate titanate [Pb(Zr_xTi_1-x)O₃], with hexagonal silicon carbide can yield high-power, high-temperature, high-frequency devices with multiple functionality. Successful integration requires an effective interface between the functional film and the wide bandgap semiconductor. Lattice mismatch between the hexagonal substrate and rhombohedral (BaM) or tetragonal (PZT) films is -4.5% and -7.3% respectively. However, crystalline magnesium oxide (MgO) is a potential bridging layer that can be integrated between the SiC substrate and the complex oxides. The O-O spacing in the MgO can be used to reduce lattice mismatch to as little as -1.3% for BaM (0001)/MgO (111) and -4.1% for PZT (111)/MgO (111). Single crystalline MgO (111) films 15 to 20 Å films have been grown on 6H-SiC and have been shown to be stable in air. The carbon-terminated surface and the silicon-terminated surface produce differently structured films under the same molecular beam epitaxy flux and fluence conditions. 6H-SiC substrates (0001)_Si and (000ī)_C were degreased in a series of solvents at 80oC and then etched in a custom built, resistively heated, hydrogen furnace under flowing high purity hydrogen (11.4 slpm) at temperatures around 1600^oC +/- 5^oC for thirty minutes. The substrate was heated at a rate of 200^oC/minute and cooled at a rate of 100^oC/minute. The temperature of the substrate was measured by a two-color optical pyrometer. This cleaning procedure has been proven to eliminate polishing scratches on the surface, create atomic steps hundreds of nanometers wide and 1.5 nm high, and reduce oxygen contamination from 12% to 8% for the silicon-terminated surface and from 8% to 3% for the carbon-terminated surface. The residual oxygen concentration was determined to by x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and reflection high energy electron diffraction (RHEED) to be incorporated into a √3×√3 R30^o silicate adlayer reconstruction. The substrates were immediately loaded into an ultra high vacuum (UHV) system and evacuated to a base pressure of 2×10^-9 Torr. MgO growth was carried out using a remote oxygen plasma source at 400 Watts and constant pressure (5×10^-6 Torr) and a solid source Mg effusion cell at various Mg fluxes but constant Mg fluence. RHEED was used in-situ to monitor the crystal structure of the MgO films in real time. Chemical analysis of the thin films was performed after MgO growth using AES and XPS. Ex-situ morphological studies included atomic force microscopy (AFM) and scanning electron microscopy (SEM). Mg flux was varied from 5x10¹³ to 2.5x10¹⁴ atoms/cm²s at constant excess O flux, producing Mg:O flux ratios between 0.02 – 0.1. For both substrate orientations, the growth rate was found to increase with Mg flux, indicating a magnesium adsorption controlled growth mechanism. Nearly stoichiometric MgO thin films grown on (0001)_Si oriented SiC substrates were three-dimensional and crystalline at low Mg flux (5x10¹³ atoms/cm²s) but became more conformal and improved single crystalline as the Mg flux was increased. The opposite was observed for (000ī)_C oriented SiC. At low Mg fluxes, at less than 1x10¹⁴ atoms/cm²s, the films were conformal but highly polycrystalline. As the Mg flux was increased, the crystalline MgO thin films became less polycrystalline but exhibited more 3-D morphology. For all MgO films, XPS analysis indicated multiple bonding states in the Mg 2p peak with a ΔeV of 1.3 eV, which corresponds to Mg-O and Mg metal. From the results observed between different orientations and Mg:O flux ratios, it is hypothesized that growth conditions alone are not responsible for the resulting stoichiometry, crystal structure and morphology of the MgO thin films. There is evidence that the starting surface chemistry may be important for controlling MgO thin film properties. In order to successfully engineer a process capable of integrating MgO as an interlayer between complex oxides and SiC, it is necessary to control and understand the effects of the 6H-SiC starting surface in order to engineer an effective interface capable of achieving high quality heteroepitaxy.