AVS 53rd International Symposium
    Electronic Materials and Processing Friday Sessions
       Session EM+TF-FrM

Paper EM+TF-FrM7
Magnesium Oxide Thin Film 'Bridge' on Hexagonal Silicon Carbide for Integration of Functional Oxides

Friday, November 17, 2006, 10:00 am, Room 2003

Session: High-k Dielectric & Multi-Functional Oxide Growth & Processing
Presenter: K.S. Ziemer, Northeastern University
Authors: T.L. Goodrich, Northeastern University
Z. Cai, Northeastern University
K.S. Ziemer, Northeastern University
Correspondent: Click to Email
Single crystalline MgO (111) films, 15 to 100 Å thick, have been grown on hexagonal silicon carbide (6H-SiC) in order to integrate complex oxides, such as lead zirconate titanate [PZT], with SiC high-power, high-temperature, high-frequency devices with multiple functionalities. 6H-SiC substrates (0001)@sub Si@ and (000I)@sub C@ were cleaned to create atomic steps hundreds of nanometers wide and 1.5 nm high, and reduce oxygen contamination from 12% to 8% for the (0001)@sub Si@ surface and from 8% to 3% for the (000I)@sub C@ surface, as measured by x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy. The residual oxygen concentration was determined by reflection high energy electron diffraction (RHEED) to be incorporated into a @sr@3x@sr@3 R30° silicate adlayer reconstruction. MgO films were grown using a remote oxygen plasma source to produce a constant chamber oxygen pressure (5x10@super -6@ Torr) and a solid source Mg effusion cell at various Mg fluxes but constant Mg fluence. The (000I)@sub C@ surface and the (0001)@sub Si@ surface of the SiC produce differently structured films, as measured by RHEED and atomic force microscopy (AFM), under the same molecular beam epitaxy growth conditions. All films are roughly stoichiometric as measured by XPS, with some suggestions of Mg metallic bonding near the substrate. MgO thin films grown on (0001)@sub Si@ oriented SiC substrates were three-dimensional and crystalline at low Mg flux but became more conformal and improved single crystalline as the Mg flux was increased. The opposite was observed for (000I)@sub C@ oriented SiC. At Mg fluxes than 1x10@super 14@ atoms/cm@super 2@s, 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. Current studies will compare the deposition of BaTiO and PZT on the MgO thin films to those deposited directly on the cleaned SiC substrates.