AVS 45th International Symposium
    Surface Science Division Wednesday Sessions
       Session SS1-WeA

Paper SS1-WeA9
Metal Row Growth on a High-Index Silicon Surface

Wednesday, November 4, 1998, 4:40 pm, Room 308

Session: Electromigration and Surface Transport
Presenter: H.H. Song, Virginia Commonwealth University
Authors: H.H. Song, Virginia Commonwealth University
K.M. Jones, Virginia Commonwealth University
S.R. Blankenship, Virginia Commonwealth University
J.A. Carlisle, Virginia Commonwealth University
A.A. Baski, Virginia Commonwealth University
Correspondent: Click to Email
Recent STM studies of high-index silicon surfaces have revealed unique morphologies not found on their low-index counterparts.@footnote 1@ For example, Si(5 5 12) forms a single-domain reconstruction composed of row-like structures, primarily pi-bonded chains. This highly anisotropic surface is expected to provide a unique template for the growth of metal overlayers, particularly in the formation of one-dimensional nanometer-scale structures. Our STM studies show that Ag deposited onto Si(5 5 12) and annealed to moderate temperatures does form row-like overlayer features. At coverages as low as 0.05 ML, rows appear on top of the most prominent pi-bonded chains, resulting in a 5.4 nm inter-row spacing. These rows have high aspect ratios (up to 40:1) and a mean length of 20 nm. As the Ag coverage is increased, the overlayer rows grow in length and number until the surface forms a periodic array of such rows at ~0.25 ML. Above this coverage, Ag appears to be incorporated into other structures on the surface and the long-range ordering becomes disrupted. A statistical analysis of the row lengths reveals the expected increase in mean row length as a function of coverage (0.05 to 0.2 ML) and annealing temperature (400 to 550°C). At annealing temperatures above 550°C, however, the deposited Ag causes local faceting of the Si surface, disrupting the ordered arrays of Ag rows. The metal rows must therefore be a metastable arrangement of the surface. @FootnoteText@ @footnote 1@A.A. Baski, S.C. Erwin, L.J. Whitman, Surf. Sci. 392, 69 (1997).