IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Semiconductors Friday Sessions
       Session SC+SS-FrM

Paper SC+SS-FrM3
Modulated Semiconductor Structures Studied by In Situ Scanning Tunneling Microscopy

Friday, November 2, 2001, 9:00 am, Room 111

Session: Growth and Epitaxy of Semiconductors
Presenter: C.A. Pearson, University of Michigan-Flint
Authors: C.A. Pearson, University of Michigan-Flint
C. Dorin, University of Michigan-Flint
Y. Chen, University of Michigan-Flint
J. Mirecki Millunchick, University of Michigan-Flint
B.G. Orr, University of Michigan-Flint
Correspondent: Click to Email
Semiconductor structures known to exhibit compositional modulation are compared to similar structures that do not exhibit compositional modulation using in situ scanning tunneling microscopy. The structures are grown by molecular beam epitaxy on InP(001) following the growth of a lattice matched InGaAs buffer layer. InAs/GaAs and InAs/AlAs short period superlattices (SPSs) can be classified as having either rough or smooth interfaces. Rough interface SPSs exhibit compositional modulation. The buffer layer and smooth interface SPSs are structures that do not exhibit compositional modulation. Images of these structures are characterized by long wavelength surface undulations. This contrasts significantly from images of modulated structures, which show both long and short wavelength surface undulations. Another distinction is that the lattice planes on the modulated structures appear much more dendritic due to the short wavelength undulations. The relationship between the morphology of the buffer layer and the resulting SPS structure is discerned through these comparisons. Segregation of species is identified as well using scanning tunneling spectroscopy. Results from proximal probe experiments will increase the atomistic understanding of surface roughness and its role in compositional modulation.