Formation of strained iron silicide nanodots by Fe deposition on Si nanodots on oxidized Si (111) surfaces
- Quantum-Phase Electronics Center, Department of Applied Physics, Graduate School of Engineering, University of Tokyo, Bunkyo-ku, Tokyo 113-8656 (Japan)
- CREST Japan Science and Technology Agency (Japan)
We studied the epitaxial growth of iron silicide ({epsilon}-FeSi,{beta}-FeSi{sub 2}, and {alpha}-FeSi{sub 2}) nanodots on Si (111) substrates by Fe deposition on Si nanodots on Si (111) substrates with ultrathin Si oxide films using reflection high-energy electron diffraction, scanning tunneling microscopy, and transmission electron microscope (TEM). We formed almost single phase iron silicide nanodots by controlling the Fe deposition conditions; growth temperature, deposition rate, and amount. The {epsilon}-FeSi or {alpha}-FeSi{sub 2} nanodots were epitaxially grown in a dome shape with an average size of {approx}5 nm and an ultrahigh density (>10{sup 12} cm{sup -2}) on the surface. We formed {approx}2-nm high and {approx}8-nm wide {beta}-FeSi{sub 2} nanodots in a dome shape with a density of {approx}5x10{sup 11} cm{sup -2} on the surface. Cross-sectional TEM images revealed that the {beta}-FeSi{sub 2} growth continued beneath the Si surface. The part of the {beta}-FeSi{sub 2} nanodot beneath the surface was a disk shape, which was {approx}5 nm thick and {approx}20 nm wide, with an abrupt interface parallel to the Si (111) plane. The nanodots were epitaxially grown and had almost no misfit dislocations near the {beta}-FeSi{sub 2}/Si interface, which were strained by the lattice mismatch. The size distribution of the iron silicide dots was determined by Ostwald ripening with the activation energy of dot edge mobility of {approx}1.3 eV.
- OSTI ID:
- 20719338
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Issue: 7 Vol. 72; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ACTIVATION ENERGY
CRYSTAL GROWTH
DENSITY
DEPOSITION
DISLOCATIONS
ELECTRON DIFFRACTION
EPITAXY
EV RANGE
FILMS
INTERFACES
IRON SILICIDES
LAYERS
OXIDATION
QUANTUM DOTS
REFLECTION
SCANNING TUNNELING MICROSCOPY
SEMICONDUCTOR MATERIALS
SILICON
SUBSTRATES
SURFACES
TRANSMISSION ELECTRON MICROSCOPY