AVS 53rd International Symposium
    Electronic Materials and Processing Thursday Sessions
       Session EM-ThP

Paper EM-ThP22
Integration of Barium Ferrite on the Wide Bandgap Semiconductor 6H-SiC Through Molecular Beam Epitaxy

Thursday, November 16, 2006, 5:30 pm, Room 3rd Floor Lobby

Session: Electronic Materials and Processing Poster Session
Presenter: Z. Cai, Northeastern University
Authors: Z. Cai, Northeastern University
Z Chen, Northeastern University
T.L. Goodrich, Northeastern University
V.G. Harris, Northeastern University
K.S. Ziemer, Northeastern University
Correspondent: Click to Email
Integration of nonreciprocal ferrite microwave devices with semiconductor platforms would allow for reduced volume and weight in phased array radar electronics, in addition to enhanced bandwidth and power management. Barium hexaferrite (BaM, BaFe@sub 12@O@sub 19@) is ideal for microwave device applications because of its large (17kOe) uniaxial magnetocrystalline anisotropy, high resistivity and permeability at high frequencies (>40GHz). The performance of current ferrite devices would be enhanced and novel devices would be possible if BaM were integrated with wide bandgap semiconductors (e.g. SiC), which can function in high-temperature, high-power, and high-frequency environments. However, oriented, single-crystalline BaM films with the desired magnetic properties (high saturation magnetization and low FMR linewidth) have not yet been successfully grown on any semiconductor substrate. In order to produce BaM thin films with desired stoichiometry, structure, and magnetic properties needed for microwave device applications, the nucleation and growth mechanisms of BaM on 6H-SiC were investigated using a remote oxygen plasma source producing a chamber oxygen pressure of 5x10@super -6@ Torr, and solid source Ba and Fe effusion cells. In-situ x-ray photoelectron spectroscopy (XPS) and reflection high-energy electron diffraction show oxygen rich (@>=@69%) and iron deficient (@<=@20%) polycrystalline films, which suggest complex surface reactions among the metals and the oxygen. Preliminary XPS studies of BaM films deposited by pulsed laser deposition (PLD) show different compositions and O bonding states with respect to the thickness of the films. Films grown on SiC by PLD are porous with either FMR linewidth of >500 Oe or no FMR at all. Using a MgO interlayer structure between the BaM and SiC has been shown to prevent silicon diffusion into BaM films and reduce bond mixing at the interface, which results in FMR linewidths <500 Oe.