AVS 47th International Symposium
    Semiconductors Tuesday Sessions
       Session SC+EL+SS-TuM

Paper SC+EL+SS-TuM1
Reconstructions and Steady-state Surface Structures on InAs(001)-(2x4): Implications for Atomistic Modeling of Growth

Tuesday, October 3, 2000, 8:20 am, Room 306

Session: Compound Semiconductors
Presenter: W. Barvosa-Carter, HRL Laboratories and University of California, Los Angeles
Authors: W. Barvosa-Carter, HRL Laboratories and University of California, Los Angeles
F. Grosse, HRL Laboratories and University of California, Los Angeles
M. Gyure, HRL Laboratories
J.H.G. Owen, HRL Laboratories and University of California, Los Angeles
C. Ratsch, HRL Laboratories and University of California, Los Angeles
R.S. Ross, HRL Laboratories
J.J. Zinck, HRL Laboratories
Correspondent: Click to Email
Heterostructures involving InAs, GaSb, and AlSb are increasingly finding applications in high-frequency, infrared, and ‘spin-tronic’ devices. Interface structure in these devices can be critical in determining device performance. The robustness of any model that seeks to relate process parameters and in-situ sensor signals to the surface chemistry or roughness of the growing film ultimately depends on our understanding of the relevant surface reconstructions and epitaxial growth mechanisms. Using MBE, RHEED, and atomic-resolution STM, we have studied the reconstructions and ‘steady-state’ surface structures present on MBE-grown InAs homoepitaxial surfaces in the (2x4) growth regime. On InAs we find two reconstructions that are relevant for growth: the familiar @beta@2(2x4) (as on GaAs) and the less familiar @alpha@2(2x4). We find excellent agreement between detailed atomic-resolution STM and first-principles simulated images of these structures. Upon quenching, we find that "steady-state" InAs surfaces exhibit small islands and adatom-like structures residing on a disordered mixture of the @beta@2 and @alpha@2 reconstructions, and that the proportions of these structures vary as a function of As pressure and temperature. Hence, the growth surface structure for InAs is remarkably different than for GaAs, where only the @beta@2 reconstruction is present with relatively few defects under device growth conditions. These results are in excellent qualitative agreement with an ab initio-based Monte Carlo model that is being developed in parallel with the experimental effort to describe reconstructions and growth on this surface.