Title :
Adsorption-Controlled Growth of BiFeO3 by MBE and Integration with Wide Band Gap Semiconductors
Author :
Ihlefeld, Jon F. ; Tian, Wei ; Liu, Zi-Kui ; Doolittle, W. Alan ; Bernhagen, Margitta ; Reiche, Peter ; Uecker, Reinhard ; Ramesh, Ramamoorthy ; Schlom, Darrell G.
Author_Institution :
Dept. of Mater. Sci. & Eng., Cornell Univ., Ithaca, NY, USA
fDate :
8/1/2009 12:00:00 AM
Abstract :
BiFeO3 thin films have been deposited on (001) SrTiO3, (101) DyScO3, (011) DyScO3, (0001) AlGaN/GaN, and (0001) 6H-SiC single crystal substrates by reactive molecular beam epitaxy in an adsorption-controlled growth regime. This is achieved by supplying a bismuth over-pressure and utilizing the differential vapor pressures between bismuth oxides and BiFeO3 to control stoichiometry in accordance with thermodynamic calculations. Four-circle x-ray diffraction and transmission electron microscopy reveal phase-pure, epitaxial films with rocking curve full width at half maximum values as narrow as 7.2 arc seconds (0.002deg). Epitaxial growth of (0001)-oriented BiFeO3 thin films on (0001) GaN, including AlGaN HEMT structures, and (0001) SiC has been realized using intervening epitaxial (111) SrTiO3 / (100) TiO2 buffer layers. The epitaxial BiFeO3 thin films have 2 in-plane orientations: [1120] BiFeO3 || [112macr0] GaN (SiC) plus a twin variant related by a 180deg in-plane rotation. This epitaxial integration of the ferroelectric with the highest known polarization, BiFeO3, with high bandgap semiconductors is an important step toward novel field-effect devices.
Keywords :
III-V semiconductors; X-ray diffraction; adsorption; aluminium compounds; bismuth compounds; buffer layers; dielectric polarisation; dysprosium compounds; epitaxial layers; ferroelectric materials; ferroelectric thin films; gallium compounds; high electron mobility transistors; molecular beam epitaxial growth; semiconductor-insulator boundaries; silicon compounds; stoichiometry; strontium compounds; thermodynamics; transmission electron microscopy; wide band gap semiconductors; AlGaN-GaN; BiFeO3; DyScO3; HEMT structures; SiC; SrTiO3; adsorption-controlled growth; buffer layers; epitaxial growth; ferroelectric epitaxial integration; field-effect device; four-circle X-ray diffraction; full width at half maximum value; polarization; reactive molecular beam epitaxy; rocking curve; stoichiometry; thermodynamic calculations; thin films; transmission electron microscopy; wide band gap semiconductors; Aluminum gallium nitride; Bismuth; Gallium nitride; Molecular beam epitaxial growth; Pressure control; Silicon carbide; Sputtering; Substrates; Thermodynamics; X-ray diffraction;
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
DOI :
10.1109/TUFFC.2009.1216