AVS 52nd International Symposium
    Surface Science Tuesday Sessions
       Session SS1-TuA

Paper SS1-TuA4
Investigations of Surface Reconstructions and 3D Roughening in InGaAs Films

Tuesday, November 1, 2005, 3:00 pm, Room 202

Session: Compound Semiconductors
Presenter: L.E. Sears, University of Michigan
Authors: L.E. Sears, University of Michigan
J.M. Millunchick, University of Michigan
C. Pearson, University of Michigan - Flint
Correspondent: Click to Email
The epitaxial growth of III-V semiconductors and their corresponding properties depend on the surface reconstructions and morphology of the film grown. We have found that the surface structure of In@sub x@Ga@sub 1-x@As alloys consists of multiple surface reconstructions depending on the composition x. The goal of this work is to determine which reconstructions are present as a function of both composition and temperature, in order to map out the surface phase diagram for this system. For example, for In@sub 0.81@Ga@sub 0.19@As/InP grown at 503°C with an As overpressure of 2.1 ML/sec and a growth rate of 1.16 ML/sec, highly ordered regions of @beta@2(2x4) coexist with more disordered regions having a (4x3) symmetry. In this case, the percentage of @beta@2(2x4) covering the surface initially increases with increasing thickness, followed by a sharp decrease that corresponds to the onset of surface roughening and 3D roughening. Previous work on In@sub 0.27@Ga@sub 0.73@As/GaAs, which has a similar lattice mismatch, shows similar disordered (4x3) regions, but the highly ordered @beta@2(2x4) regions have been replaced by @alpha@2(2x4) regions.@footnote 1@ It is postulated that the (4x3) surface reconstruction is a unique alloy structure, while the (2x4) reconstructions are enriched in In. @FootnoteText@ @footnote 1@ Millunchick JM, Riposan A, Dall B, Pearson C, and Orr BG, Surf. Sci. 550 (1-3): 1-7 FEB 10 2004.