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Open Access. Powered by Scholars. Published by Universities.®

1994

Biology

Strain

Articles 1 - 3 of 3

Full-Text Articles in Life Sciences

Strain Relaxation In Compositionally Graded Ingaas/Gaas Heterostructures, Karen L. Kavanagh, Rachel S. Goldman, Jessica C. P. Chang Dec 1994

Strain Relaxation In Compositionally Graded Ingaas/Gaas Heterostructures, Karen L. Kavanagh, Rachel S. Goldman, Jessica C. P. Chang

Scanning Microscopy

Epilayer strain relaxation in the InGaAs/GaAs system occurs via two mechanisms, plastic deformation and/or surface roughening. Under conditions of two-dimensional growth, we find that compositionally graded InGaAs/GaAs (001) multi-layer buffer structures will plastically deform with < 110 > misfit dislocations approaching 100% strain relaxation. At higher growth temperatures, large-amplitude roughening is observed preferentially along the [110] direction, and the strain relaxation becomes asymmetric in the < 110 > directions. In single epilayers, the symmetry of the strain relaxation is dependent on the magnitude of the substrate offcut angle. In all cases, the epilayers develop a tilt about an in-plane axis in proportion to and opposite in …


X-Ray Absorption Studies Of Strain In Epitaxial (Si-Ge) Atomic Layer Superlattice And Alloy Films, T. Tyliszczak, A. P. Hitchcock, Z. H. Lu, J. -M. Baribeau, T. E. Jackman Dec 1994

X-Ray Absorption Studies Of Strain In Epitaxial (Si-Ge) Atomic Layer Superlattice And Alloy Films, T. Tyliszczak, A. P. Hitchcock, Z. H. Lu, J. -M. Baribeau, T. E. Jackman

Scanning Microscopy

The Si 1s (K-shell) X-ray absorption spectra of a series of strained SixGe100-x alloy thin films and several {(Si)m(Ge)n}p atomic layer superlattices (ALS) grown epitaxially on Si(100) and Ge(100) substrates have been investigated using plane polarized synchrotron radiation. Polarization dependent components of the signal are attributed to anisotropic states associated with strain-induced tetragonal distortions. The sense of the polarization is shown to be identical for all compositions (x = 25 to 92) of SiGe alloys grown on Si(100) substrates. The opposite polarization dependence is found to occur for all SixGe …


Interfacial Studies In Semiconductor Heterostructures By X-Ray Diffraction Techniques, J. -M. Baribeau, R. L. Headrick, P. Maigné Dec 1994

Interfacial Studies In Semiconductor Heterostructures By X-Ray Diffraction Techniques, J. -M. Baribeau, R. L. Headrick, P. Maigné

Scanning Microscopy

X-ray radiation is a non-destructive probe well suited to assess structural perfection of semiconductor material. Three techniques are used to study the interfacial roughness, period fluctuations and annealing-induced interdiffusion in various superlattice structures. Reflectivity of long period Si/Si1-xGex multiple quantum wells reveals an asymmetry oriented along the direction of miscut in the interface roughness with the Si1-xGex to Si interfaces being about twice as rough (0.5 versus 0.3 nm) as the Si to Si1-xGex interfaces. For Si-Si0.65Ge0.35 multiple quantum wells, diffuse scattering is minimal for a growth temperature …