Stability of MgO(1 1 1) films grown on 6H-SiC(0 0 0 1) by molecular beam epitaxy for two-step integration of functional oxides

• Published in: Applied surface science Vol. 254; no. 10; pp. 3191 - 3199
• Main Authors: Goodrich, T.L., Cai, Z., Ziemer, K.S.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.03.2008; Elsevier Science
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electron and ion emission by liquids and solids; impact phenomena; Electron diffraction and scattering; Exact sciences and technology; Functional oxides; Heteroepitaxy; Low-energy electron diffraction (leed) and reflection high-energy electron diffraction (rheed); Materials science; MBE; Methods of deposition of films and coatings; film growth and epitaxy; MgO; Molecular, atomic, ion, and chemical beam epitaxy; Photoemission and photoelectron spectra; Physics; SiC; Structure of solids and liquids; crystallography; Wide bandgap semiconductor; MBE; MgO; Functional oxides; Heteroepitaxy; SiC; Wide bandgap semiconductor; 81.15.Hi 79.60.−i; Oxygen; Inorganic compounds; Semiconductor materials; Magnesium oxide; Pulsed laser deposition; Etching; MgO; SiC; Heteroepitaxy; Functional oxides; MBE; Wide bandgap semiconductor; Film growth; Interface structure; Silicon carbide; Molecular beam epitaxy; 81.15.Hi 79.60.-i
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2007.10.077

Crystalline magnesium oxide (MgO) (1 1 1), 20 Å thick, was grown by molecular beam epitaxy (MBE) on hydrogen cleaned hexagonal silicon carbide (6H-SiC). The films were further heated to 740 °C and 650 °C under different oxygen environments in order to simulate processing conditions for subsequent functional oxide growth. The purpose of this study was to determine the effectiveness and stability of crystalline MgO films and the MgO/6H-SiC interface for subsequent heteroepitaxial deposition of multi-component, functional oxides by MBE or pulsed laser deposition processes. The stability of the MgO films and the MgO/6H-SiC interface was found to be dependent on substrate temperature and the presence of atomic oxygen. The MgO films and the MgO/6H-SiC interface are stable at temperatures up to 740 °C at 1.0 × 10 −9 Torr for extended periods of time. While at temperatures below 400 °C exposure to the presence of active oxygen for extended periods of time has negligible impact, exposure to the presence of active oxygen for more than 5 min at 650 °C will degrade the MgO/6H-SiC interface. Concurrent etching and interface breakdown mechanisms are hypothesized to explain the observed effects. Further, barium titanate was deposited by MBE on bare 6H-SiC(0 0 0 1) and MgO(1 1 1)/6H-SiC(0 0 0 1) in order to evaluate the effectiveness of the MgO as a heteroepitaxial template layer for perovskite ferroelectrics.