Photoemission study of the CoSi/sub 2/(111)--Si surface

Journal Article · Mon May 01 04:00:00 EDT 1989 · J. Vac. Sci. Technol., A; (United States)

DOI:https://doi.org/10.1116/1.575919· OSTI ID:6336280

Rowe, J E; Wertheim, G K; Tung, R T

Epitaxial CoSi/sub 2/ terminated with a thin Si bilayer has been studied by synchrotron radiation photoemission. This well-defined surface phase of CoSi/sub 2/ is obtained by high-temperature annealing in the range 450--650 /sup 0/C. The samples used were prepared by molecular-beam epitaxy techniques with a film thickness of /similar to/800 A on Si(111) substrates and capped with a /similar to/100 A film of a-Si to act as an oxide barrier while samples were transferred to the photoemission chamber. The surfaces studied by photoemission were prepared by careful sputtering to remove the oxide and a-Si layer and then anealed to /similar to/450--650 /sup 0/C for 1 min. Photoemission spectra were taken with total resolution in the range 200--237 meV and show evidence for four spin--orbit doublets. Our samples and results are somewhat different from those of previous studies of thin CoSi/sub 2/ films or studies of bulk CoSi/sub 2/ samples. We find three surface Si(2p) components: one shifted to higher binding energy and two shifted below the main Si(2p) spin-orbit doublet in CoSi/sub 2/. We find the Si(2p/sub 3/2/ ) energy in CoSi/sub 2/ is 99.40 eV measured with respect to the Fermi level; the three surface-shifted Si components are at -0.75, 0.17, and -0.18 eV relative to the main component in order of decreasing intensity and thus layer distance from the surface. A structural model previously proposed for thin CoSi/sub 2/ layers is shown to be qualitatively consistent with these results.

• Research Organization: ATandT Bell Laboratories, Murray Hill, New Jersey 07974
• OSTI ID: 6336280
• Journal Information: J. Vac. Sci. Technol., A; (United States), Journal Name: J. Vac. Sci. Technol., A; (United States) Vol. 7:3; ISSN JVTAD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
COATINGS
COBALT COMPOUNDS
COBALT SILICIDES
CRYSTAL GROWTH
CRYSTAL STRUCTURE
DATA
ELEMENTS
EMISSION
EMISSION SPECTROSCOPY
EPITAXY
EXPERIMENTAL DATA
FILMS
INFORMATION
INTERFACES
MOLECULAR BEAM EPITAXY
NUMERICAL DATA
PHOTOEMISSION
SECONDARY EMISSION
SEMIMETALS
SILICIDES
SILICON
SILICON COMPOUNDS
SPECTROSCOPY
SUBSTRATES
SURFACE PROPERTIES
THIN FILMS
TRANSITION ELEMENT COMPOUNDS