Cheung, N.

Feldman, L. C.

Silverman, P. J.

Stensgaard, I.

English

Caltech Authors - Main

Abstract: MeV ion scattering from thin Si single crystals: A 
novel approach to interface studies 
L. C. Feldman, P. J. Silverman, and I. Stensgaard 
Bell Laboratories, Murray Hill, New Jersey 07974 
N. Cheung 
Department of Applied Physics, California Institute of Technology, Pasadena, California 91125 
(Received 13 September 1979) 
PACS numbers: 68.20. + t, 79.20.Nc, 61.80.Jh, 61.80.Mk 
MeV ion scattering, in combination with channeling, provides 
a quantitative non-destructive method for determining the 
stoichiometry of amorphous layers on semiconductors and the 
reconstruction of the single crystal substrate. The interpre-
tation and sensitivity of the technique depend on proper 
knowledge of the ion beam flux distribution and the thermal 
displacements of the atoms in the unreconstructed monolayers 
of the single crystal surface. We describe measurements of 
the scattering intensity from thin ("-'0.5 f.lm) Si crystals with 
thin oxides. The ion beam flux distribution is modified in 
channeling through such thin crystals so that the beam at the 
exit surface scatters primarily from atoms with large dis-
placements from the atomic strings. The scattering spectrum 
from the beam exit side therefore displays a peak which 
represents only those channeled ions which have scattered 
from Si atoms in the oxide and from sufficiently displaced 
atoms in the reconstructed layers of the substrate. The in-
tensity of this peak indicates that the native oxide is stoi-
chiometric to within a few monolayers of the substrate, con-
firming the sharp interface previously reported. 1 New in-
formation on the reconstruction at the Si interface is extracted 
and indicates that no more than two monolayers of Si are 
displaced substantially from their "bulk" positions. Possibilities 
for studies of metal-Si interfaces will also be discussed. 
Acknowledgment: Work performed as a resident visitor 
at Bell Laboratories. 
1L. C. Feldman, I. Stensgaard, P. J. Silverman, and T. E. Jackman in The 
Physics of Si02 and Its Interfaces, edited by S. T. Pantelides (Pergamon, 
New York, 1978), p. 344. 
1457 J. Vac. Sci. Techno!., 16(5), Sept./Oct. 1979 0022-5355/79/051457-01$01.00 © 1979 American Vacuum Society 1457 


MeV ion scattering from thin Si single crystals: A

novel approach to interface studies

http://authors.library.caltech.edu/32722/1/FELjvst79.pdf

MeV ion scattering from thin Si single crystals: A novel approach to interface studies

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