A New Model for the Cleaved Si (111)-(2x1) Surface
There is currently general agreement about the structures of Si(100) and annealed Si(111) (7×7) surfaces, but the situation for the cleaved Si(111) (2×1) surface is less satisfactory . A Si crystal in the (111) orientation can be viewed as a series of tetrahedra with one bond vertical and the other three forming the base, resulting in a structure that consists of double layers of closely spaced atomic planes (d = 0.78 Å) separated from each other by the Si interatomic distance d = 2.35 Å. All of the existing models use as their basis the assumption that in cleavage, the one bond that is oriented normal to the (111) surface breaks, so that the termination is the closely-spaced-layer pair that then reconstructs to form the (2×1) surface.
KeywordsDouble Layer Partial Dislocation Break Bond Charge Cloud Original Dislocation
Unable to display preview. Download preview PDF.
- 6.P. B. Hirsch, J. Physique, Coll. C6, 40, 27 (1979); A. Ourmadz, G. R. Anstis, and P. B. Hirsch, Philos. Mag. A48, 139 (1983).Google Scholar
- 7.P. B. Hirsch, J. Electr. Micros. 118, 3 (1980).Google Scholar
- 8.H. Alexander, J. C. H. Spence, D. Shindo, H. Gottschalk, and N. Long, Philos. Mag. A53, 627 (1986).Google Scholar
- J. P. Hirth and J. Lothe, Theory of Dislocations, (McGraw-Hill, New York 1968).Google Scholar
- 10.There are a number of measurements and calculations. For a first- principles calculation and listing of earlier work, see M. Y. Chou, M. L. Cohen, and S. G. Louie, Phys. Rev. B32 7979 (1985).Google Scholar
- 11.D. J. H. Cockayne, private communication; D. J. H. Cockayne, A. Hons, and J. C. H. Spence, Micron 11, Suppl. 1, 32 (1980).Google Scholar
- 15.For a review, see S. S. Brenner, In: Fiber Composite Materials, ASM, Metals Park (1985).Google Scholar
- 16.D. M. Marsh, In: Fracture of Solids, ed. by D. C. Drucker and J. J. Gilman, (Interscience, New York 1963). See also R. L. Mehan and J. A. Herzog, In: Whisker Technology, ed. by A. P. Levitt, (Wiley- Interscience, New York 1970).Google Scholar
- 17.This structure is similar to that obtained by arbitrarily adding adatom chains onto the ideal (111) surface, as suggested by R. Sciwatz, Surface Sci. 2, 473 (1964). To create adatoms requires thermal treatment sufficient to give atomic transport at the surface, and thus a structure involving adatoms is not directly applicable to a cleaved surface. In the present model for the cleavage process, the chains are an integral part of the structure, being the normal outermost layer.Google Scholar
- 20.A more extensive exposition of these concepts will be presented elsewhere. D. Haneman and M. G. Lagally, J. Vac. Sci. Techno!. A6_ (1988) (submitted).Google Scholar