AVS 47th International Symposium
    Surface Science Wednesday Sessions
       Session SS-WeP

Paper SS-WeP9
Effects of Al/Si(111) Surface Phases on the Wandering of the Single-Height Steps@footnote 1@

Wednesday, October 4, 2000, 11:00 am, Room Exhibit Hall C & D

Session: Poster Session
Presenter: I. Lyubinetsky, University of Maryland, College Park
Authors: I. Lyubinetsky, University of Maryland, College Park
D.B. Dougherty, University of Maryland, College Park
H.L. Richards, University of Maryland, College Park
T.L. Einstein, University of Maryland, College Park
E.D. Williams, University of Maryland, College Park
Correspondent: Click to Email
The thermally-induced wandrering of single-height steps have been studied by STM on a vicinal Si(111) surface, miscut by 0.5° in the [2,-1,-1] direction, after aluminum deposition at elevated temperatures (500-700°C). From direct measurement of the step-correlation function, the step diffusivity, b@super2@/a, is shown to increase strongly as Al coverage @Theta@ in the surface phases increases: b@super2@/a ~ 0.4 Å for the a(7x7) phase (@Theta@ = 0.12 ML), ~ 1.5 Å for the (@sr@3x@sr@3) phase (@Theta@ = 0.3 ML), and ~ 4.6 Å for the @gamma@ phase, also referred to as the (9.4x9.4) phase, (@Theta@ = 0.68 ML), implying corresponding systematic decrease in the kink energy. An increase of the step diffusivity compared to a clean Si(111)-(7x7) surface has been observed even at the very initial stages of the a(7x7) reconstruction formation, at @Theta@ as low as 0.02 ML. For the least stable phase of (@sr@7x@sr@7) (@Theta@ = 0.43 ML), which coexists with the @gamma@ phase on the same terrace, the wandering of the phase boundaries between (@sr@7x@sr@7) and @gamma@ phases will also been discussed. @FootnoteText@ @footnote 1@Work supported by the UMD-NSF-MRSEC.