Thumbnail
Access Restriction
Open

Author Lange, R. ♦ Junge, K. E. ♦ Zollner, S. ♦ Iyer, S. S. ♦ Powell, A. P. ♦ Eberl, K.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword MATERIALS SCIENCE ♦ SILICON CARBIDES ♦ MOLECULAR BEAM EPITAXY ♦ GERMANIUM CARBIDES ♦ STRESSES ♦ DIELECTRIC TENSOR ♦ ELLIPSOMETRY ♦ ABSORPTION SPECTRA ♦ SPECTRAL SHIFT ♦ ENERGY-LEVEL TRANSITIONS ♦ DIELECTRIC FUNCTION
Abstract Using spectroscopic ellipsometry, we measured the pseudodielectric function of Si{sub 1{minus}{ital x}{minus}{ital y}}Ge{sub {ital x}}C{sub {ital y}} alloys (0{le}{ital x}{le}0.48,0{le}{ital y}{le}0.05) grown on Si(001) using molecular beam epitaxy. For pseudomorphically strained layers, the energy shifts of the {ital E}{sub 1}, {ital E}{sub 1}+{Delta}{sub 1}, {ital E}{sub 0}{sup {prime}}, and {ital E}{sub 2} transitions are determined by line shape analysis and are due to alloy composition effects, as well as hydrostatic and shear strain. We developed expressions for hydrostatic and shear shift from continuum elasticity theory, using deformation potentials for Si and Ge, for biaxial stress parallel to the (001) growth plane in a diamond or zinc blende-type crystal and applied this to the ternary Si{endash}Ge{endash}C alloy. The energies of {ital E}{sub 1} and its spin-orbit split partner {ital E}{sub 1}+{Delta}{sub 1} agree fairly well with theory. The {ital E}{sub 2} transitions in Si{sub 1{minus}{ital x}}Ge{sub {ital x}} at around 4.3 eV depend linearly on Ge concentration. In case of relaxed layers, the {ital E}{sub 1} and {ital E}{sub 1}+{Delta}{sub 1} transitions are inhomogeneously broadened due to the influence of misfit and threading dislocations. For a silicon cap on top of a dislocated, relaxed SiGe layer, we recovered the bulk Si dielectric function. {copyright} {ital 1996 American Institute of Physics.}
ISSN 00218979
Educational Use Research
Learning Resource Type Article
Publisher Date 1996-10-01
Publisher Department Ames National Laboratory
Publisher Place United States
Journal Journal of Applied Physics
Volume Number 80
Issue Number 8
Organization Ames National Laboratory


Open content in new tab

   Open content in new tab