IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Electronics Wednesday Sessions
       Session EL-WeM

Paper EL-WeM3
Step Fluctuations on a Chemically Heterogeneous Surface: Al/Si(111)-(@sr@3x@sr@3)@footnote 1@

Wednesday, October 31, 2001, 9:00 am, Room 124

Session: Si Surface Dynamics and Reactions
Presenter: I. Lyubinetsky, University of Maryland at College Park
Authors: I. Lyubinetsky, University of Maryland at College Park
D.B. Dougherty, University of Maryland at College Park
E.D. Williams, University of Maryland at College Park
Correspondent: Click to Email
Analysis of equilibrium step fluctuations has been extended for an adsorbate-induced reconstruction. The lateral and temporal correlations of single-height step fluctuations has been studied with variable temperature STM at 550-750° C on a vicinal Si(111) surface, miscut by 0.5° in the [2,-1,-1] direction, after formation of the Al-induced (@sr@3x@sr@3) surface phase. From direct measurement of the spatial step-correlation function, the step diffusivity, b@super 2@/a, is found to exponentially increase from 0.7 Å at 550°C to 1.19 Å at 750°C. The effective kink creation energy of 0.14 eV then has been extracted from corresponding Arrhenius plot. Results of analysis of lateral step correlations at elevated temperatures will also be compared with results obtained in traditional way by quenching surface down to the room temperature. The temporal correlation functions in this temperature region are shown to scale as t@super 1/2@, consistent with either step-edge attachment or terrace-crossing diffusion as a rate limiting process. The prefactor of the temporal correlation function also varies exponentially with temperature yielding an effective activation energy of 2.5 eV for the rate-limiting step in surface mass transport. Using both lateral and temporal correlation functions, the kinetic parameters governing mass transport have been extracted for different temperatures, and atomistic models for the step fluctuations will be discussed. @FootnoteText@ @footnote 1@ Work supported by the UMD-NSF-MRSEC.