AVS 50th International Symposium
    Semiconductors Thursday Sessions
       Session SC-ThM

Paper SC-ThM5
Effects of InAlSb Buffer Layers on the Structural and Electronic Properties of InSb Films

Thursday, November 6, 2003, 9:40 am, Room 326

Session: Heteroepitaxy and Strain Engineering
Presenter: X. Weng, University of Michigan
Authors: X. Weng, University of Michigan
N.G. Rudawski, University of Michigan
R.S. Goldman, University of Michigan
D.L. Partin, Delphi Research and Development Center
J. Heremans, Delphi Research and Development Center
Correspondent: Click to Email
InSb is useful for a variety of device applications, including long wavelength light sources and magnetoresistive sensors. InSb films are generally grown on GaAs substrates, with a 14.6% lattice mismatch which results in a high density of threading dislocations. In earlier work, we showed that electron scattering from the strain field associated with threading dislocations is the primary mobility-limiting mechanism in highly mismatched InSb films.@footnote 1@ The electron mobility of InSb films increases with the film thickness due to the decrease of threading dislocation density. Recently, highly mismatched resistive buffers such as InAlSb showed promise for increasing the electron mobility of thin InSb films.@footnote 2@ However, the mechanisms of buffer strain relaxation and the consequent increase in InSb electron mobility are not well understood. Thus, we have studied the effects of In@sub0.94@Al@sub0.06@Sb buffers on the structural and electronic properties of InSb films. We find a significant increase of electron mobility for InSb films grown on In@sub0.94@Al@sub0.06@Sb buffers, in comparison with those grown directly on GaAs. Cross-sectional transmission electron microscopy (TEM) reveals bending of threading dislocations at the InSb/In@sub0.94@Al@sub0.06@Sb interface, suggesting that the InSb/In@sub0.94@Al@sub0.06@Sb heterojunction plays an important role in suppressing the propagation of threading dislocations. Plan-view TEM shows a more than 50% decrease of threading dislocation densities in InSb films grown on In@sub0.94@Al@sub0.06@Sb layers compared with those grown directly on GaAs, suggesting that the electron mobility increase is likely due to the reduction in dislocation density. The effects of the buffer composition on the structure and properties of the InSb films will also be discussed. @FootnoteText@@footnote 1@ X. Weng, R.S. Goldman, D.L. Partin, and J.P. Heremans, J. Appl. Phys. 88, 6276 (2000). @footnote 2@D.L. Partin, J. Heremans, and C.M. Thrush, J. Vac. Sci. Technol. B 17, 1267 (1999).