Nucleation, growth, and strain relaxation of lattice-mismatched 3-5 semiconductor epitaxial layers (original) (raw)
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Growth and characterization of InAs epitaxial layer on GaAs(111)B
Physical Review B, 2004
The behavior of InAs deposition on GaAs͑111͒B substrates and the corresponding routes toward strain relaxation have been investigated. InAs growth was for depositions ranging from 2 monolayers to 30 monolayers. Over this deposition range, different routes for strain relaxation caused by the lattice mismatch were observed. The strain relaxed through ragged step edge formation and GaIn intermixing for low InAs deposition and through the formation of step bunching and dislocations for thicker depositions.
Microstructure of lateral epitaxial overgrown InAs on (100) GaAs substrates
Applied Physics Letters, 2003
Substantial defect reduction was achieved in InAs/GaAs by lateral epitaxial overgrowth in which InAs was grown on mask-patterned ͑100͒ GaAs with stripe-shaped windows of various widths by metalorganic chemical vapor deposition. The InAs growth morphology, crystal quality, and microstructure were evaluated using double-crystal x-ray rocking curves and scanning and transmission electron microscopy. The microstructure of the InAs grown on mask-free control samples was comprised of micron-scale misoriented grains and dislocations at a density of 10 11 cm Ϫ2. As the width of the mask openings decreased to 0.8 m, the rocking curves narrowed, grain boundaries disappeared and the dislocation density decreased to Ͻ10 7 cm Ϫ2. The distribution of the remaining defects suggests substantial changes in microstructural development when the window width is Շ1 m.
Influence of the Growth Mode on the Microstructure of Highly Mismatched InAs/GaAs Heterostructures
Physica Status Solidi (a), 1994
The lattice defect structures at highly mismatched InAs/GaAs interfaces are studied by transmission electron microscopy. The InAs films are grown by molecular beam epitaxy under various conditions resulting in different growth modes which strongly affect the relaxation process. In the Stranski-Krastanov mode, the strain is relieved first by formation of coherent islands and then by misfit dislocation generation near the interface. On the contrary, during two-dimensional growth only pure edge-type dislocations forming an orthogonal network directly at the interface are detected. I) Heisenbergstr. 1, D-70569 Stuttgart, Federal Republic of Germany. ' ) Hausvogteiplatz 5/7,
Theoretical Investigations for Strain Relaxation and Growth Mode of InAs Thin layers on GaAs(111)A
Condensed Matter
The growth mode of InAs/GaAs(111)A is systematically investigated using our macroscopic theory with the aid of empirical potential calculations that determine parameter values used in the macroscopic theory. Here, stacking-fault tetrahedron (SFT) found in InAs/GaAs(111)A and misfit dislocation (MD) formations are employed as strain relaxation mechanisms. The calculated results reveal that the MD formation occurs at the layer thickness h about 7 monolayers (MLs). Moreover, we found that the SFT forming at h about 4 MLs makes surface atoms move upward to reduce the strain energy to promote the two dimensional (2D) growth. Therefore, the SFT in addition to the MD plays an important role in strain relaxation in InAs thin layers on GaAs(111)A. The macroscopic free energy calculations for the growth mode imply that the InAs growth on the GaAs(111)A proceeds along the lower energy path from the 2D-coherent (h ≤ 4 MLs) to the 2D-MD (h ≥ 7 MLs) via the 2D-SFT (4 MLs ≤ h ≤ 7 MLs). Consequently, the 2D growth on the InAs/GaAs(111)A results from strain relaxation due to the formation of the SFT near the surface and the subsequent MD formation at the interface.
Self-assembled InAs island formation on GaAs (110) by metalorganic vapor phase epitaxy
Applied Surface Science, 2008
Formation of self-assembled InAs 3D islands on GaAs (1 1 0) substrate by metal organic vapor phase epitaxy has been investigated. Relatively uniform InAs islands with an average areal density of 10 9 cm À2 are formed at 400 C using a thin InGaAs strain reducing (SR) layer. No island formation is observed without the SR layer. Island growth on GaAs (1 1 0) is found to require a significantly lower growth temperature compared to the more conventional growth on GaAs (1 0 0) substrates. In addition, the island height is observed to depend only weakly on the growth temperature and to be almost independent of the V/III ratio and growth rate. Low-temperature photoluminescence at 1.22 eV is obtained from the overgrown islands. #
Physica E: Low-dimensional Systems and Nanostructures, 2009
Thin InAs epilayers were grown on GaAs(1 0 0) substrates exactly oriented and misoriented toward [111]A direction by atmospheric pressure metalorganic vapor phase epitaxy. InAs growth was monitored by in situ spectral reflectivity. Structural quality of InAs layers were studied by using highresolution X-ray diffraction. No crystallographic tilting of the layers with respect to any kind of these substrates was found for all thicknesses. This result is discussed in terms of In-rich growth environment. InAs layers grown on 21 misoriented substrate provide an improved crystalline quality. Surface roughness of InAs layers depend on layer thickness and substrate misorientation.
Strain relaxation in InAs heteroepitaxy on lattice-mismatched substrates
Scientific Reports, 2020
Strain relaxation processes in InAs heteroepitaxy have been studied. While InAs grows in a layer-by-layer mode on lattice-mismatched substrates of GaAs(111)A, Si(111), and GaSb(111)A, the strain relaxation process strongly depends on the lattice mismatch. The density of threading defects in the InAs film increases with lattice mismatch. We found that the peak width in x-ray diffraction is insensitive to the defect density, but critically depends on the residual lattice strain in InAs films.
2000
ABSTRACT Scanning tunneling microscopy and reflection high-energy electron diffraction under ultrahigh vacuum conditions were used to make an in situ study of atomic structures at the surface of an InAs/GaAs heterostructure grown by molecular-beam epitaxy. It was observed that the deposition of approximately 0.3 ML of indium on an arsenic-enriched GaAs(001)-2 × 4 surface leads to the formation of the 4 × 2 phase while the deposition of 0.6 ML indium leads to the appearance of a new 6 × 2 reconstruction. It is shown that layer-by-layer two-dimensional epitaxial growth of InAs on GaAs(001) as far as 13 monolayers can only be achieved if the growth front reproduces the 4 × 2 or 6 × 2 symmetry of the substrate and models of 4 × 2 and 6 × 2 reconstructions are proposed. Atomic-resolution images of faceted planes on the surface of three-dimensional islands in an InAs/GaAs(001) system were obtained for the first time and structural models of these were developed.
Assembling strained InAs islands by chemical beam epitaxy
Solid-state Electronics, 1996
We report on coherently strained InAs quantum-dots grown by chemical beam epitaxy on GaAs. The morphological phase transition of the InAs layer from two-dimensional to three-dimensional was characterized with reflection high-energy electron diffraction. The transition is found to be quasi-equilibrium in the slow deposition regime studied, to be approximately linear in InAs thickness, and to be suppressed both by higher