Growth and characterization of epitaxial metastable (gallium arsenide)(1-x)(silicon(2))(x) alloys and (gallium arsenide)(1-x)(silicon(2))(x)/gallium arsenide strained-layer superlattices

Single-crystal metastable (GaAs)$\sb{\rm 1-x}$(Si$\sb2)\sb{\rm x}$ alloys with x $\leq$ 0.57 have been grown on GaAs(001) using a hybrid sputter deposition technique. Triple-crystal x-ray diffraction studies showed that the full-width at half maximum intensity of alloys with x $\leq$ 0.4 were nearly equal to those of the GaAs substrates ($\approx$30 arc-sec) and that the lattice constants, uncorrected for strain, varied linearly between values for GaAs and Si. Alloys with 0 $\leq$ x $\leq$ 0.20 were shown by cross-sectional and plan-view transmission electron microscopy to be dislocation free. Film/substrate lattice misfit strain in alloys with 0.11 $\leq$ x $\leq$ 0.20 was partially accommodated by the formation of an epitaxial interfacial spinodal zone whose height varied from $\approx$20 to 70 nm. The spinodal region consists of lenticular platelets along the (001) growth direction and a Si-rich-(GaAs)$\sb{\rm 1-x}$(Si$\sb2)\sb{\rm x}$/Si-deficient-(GaAs)$\sb{\rm 1-x}$(Si$\sb2)\sb{\rm x}$ compositional modulation orthogonal to the growth direction. Films with x $\geq$ 0.2 exhibited, together with the interfacial zones, inhomogeneously distributed a/2 $\langle$110$\rangle$-type threading dislocations. Antiphase domains extending in the (001) growth direction with $\{$011$\}$ boundaries in plan-view which annihilated each other with increasing film thickness were observed in alloy films with x $\geq$ 0.25. GaAs overlayer experiments strongly indicated that spinodal decomposition in (GaAs)$\sb{\rm 1-x}$(Si$\sb2)\sb{\rm x}$ is not surface initiated but occurs via a solid state transformation.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Engineering, Metallurgy

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Mei, Din-How

Contributors dc:contributor

• Greene, Joseph E.

• Engineering, Metallurgy
• Engineering, Materials Science

Statement dc:rights

• Copyright 1991 Mei, Din-How

Language dc:language

eng

Identifier

AAI9210914
(UMI)AAI9210914

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/22526