Interface engineering for improved growth of GaSb on Si(111) (original) (raw)
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Lattice-registered growth of GaSb on Si (211) with molecular beam epitaxy
Journal of Applied Physics, 2012
A GaSb film was grown on a Si(211) substrate using molecular beam epitaxy indicating full lattice relaxation as well as full lattice registration and dislocation-free growth in the plane perpendicular to the [01 À 1]-direction. Heteroepitaxy of GaSb on a Si(211) substrate is dominated by numerous first order and multiple higher order micro-twins. The atomic-resolved structural study of GaSb films by high-angle annular dark-field scanning transmission electron microscopy reveals that slight tilt, along with twinning, favors the lattice registry to Si(211) substrates. Preferential bonding of impinging Ga and Sb atoms at the interface due to two distinctive bonding sites on the Si(211) surface enables growth that is sublattice-ordered and free of anti-phase boundaries. The role of the substrate orientation on the strain distribution of GaSb epilayers is further elucidated by investigating the local change in the lattice parameter using the geometric phase analysis method and hence effectiveness of the lattice tilting in reducing the interfacial strain was confirmed further.
Japanese Journal of Applied Physics
The single crystalline III-V films on substrates such as silicon and germanium are preferred by researchers to enhance the performance of a MOSFET or CMOS. In this study, we investigated the possible factors responsible for generating twin crystal growth for III-antimonides, especially GaSb grown on Si(111). We tested several base templates such as Si(111)-√3 × √3-Ga, Si(111)-√3 × √3-In, Si(111)-direct, and we have varied the growth conditions through varying the substrate temperature and growth rate. The molecular beam epitaxy growth method was used to deposit GaSb films. Our results reflect that in absence of an initial layer of GaSb film grown at a low substrate temperature, the anti-phase domains and defect densities cannot be reduced which results in the formation of twin crystal. We found that the high substrate temperature during the growth is the deciding factor in generating twin crystal growth.
Epitaxial growth of GaSb(111) on Sb(111) by interdiffusion assisted molecular beam epitaxy
Surface Science, 1995
GaSb has been grown epitaxially on Sb(ll1) substrates. Epitaxial growth occurs due to the interdiffkion when gallium is evaporated onto heated Sb substrates. We have studied the influence of the substrate temperature and of the gallium flux on the interdiffusion and the resulting layer quality and stoichiometry by reflection high energy electron diffraction (RHEED), X-ray photoelectron spectroscopy (XPS) an: Raman spectroscopy. The best layers were obtained at a substrate temperature of about 300°C and a growth rate of 0.25 A s-l.
physica status solidi (a), 2019
The growth of GaSb on Ge (111) vicinal substrates is performed by molecular beam epitaxy with Bi irradiation previous to and during the growth. The effects of the Bi irradiation on the surface morphology and on the crystallinity are investigated using atomic force microscopy and X-ray diffraction, respectively. It is shown that Bi works as a surfactant, which suppresses the generation of rotational twins in the GaSb layer.
GaSb on Si: Structural Defects and Their Effect on Surface Morphology and Electrical Properties
MRS Proceedings, 2014
ABSTRACTThe paper reports on the growth of group III-Sb’s on silicon, substrate preparation, optimization of AlGaSb metamorphic buffer, formation of defects (threading dislocations, microtwins and anti-phase boundaries) and their effect on the surface morphology and electrical properties of these high hole mobility materials for future III-V CMOS technology. Defect density was found to be 2-3x higher than in similar structures grown on GaAs, resulting in 2x higher roughness. Defects also result in background p-type doping well above 1017 cm-3 causing inversion of polarity from n-type to p-type in thin n-type doped GaSb. MOS Capacitors fabricated on these buffers demonstrate similar characteristics to higher quality GaSb-on-GaAs. The highest hole mobility obtained in a strained InGaSb QW MOS channel grown on silicon is ∼630 cm2/V-s which is ∼30% lower than similar channels grown on GaAs substrates.
Influence of Substrate Preparation on the Morphology of GaSb Films Grown by Molecular Beam Epitaxy
Journal of The Electrochemical Society, 1985
The chemical etching of (100)-oriented GaSb substrate by several different treatments has been studied. The morphology of the MBE-grown GaSb films strongly depends on the substrate preparation prior to epitaxial growth. It is shown that some defects which originate at the substrate propagate to the surface of the films, in case of the improper chemical treatment, and degrade the morphology of the films. The excellent surface morphology of the film could be obtained reproducibly by treating the substrate with CH~COOH-HNO3-HF and subsequent HNO3-HC1 solutions.
Formation of a Thin Continuous GaSb Film on Si(001) by Solid Phase Epitaxy
Nanomaterials
Nanocrystalline GaSb films were grown on Si(001) from the stoichiometric Ga–Sb mixture using solid-phase epitaxy at temperatures of 200–500 °C. Use of the solid-phase epitaxy method allowed the suppression of Ga surface diffusion and prevention of intense Sb desorption. At the annealing temperature of 300 °C, a 14-nm-thick GaSb film aggregates, while a 20-nm-thick GaSb film remains continuous with a roughness of 1.74 nm. A GaSb film with a thickness of 20 nm consists of crystalline grains with a size of 9–16 nm. They were compressed by ~2%. For some GaSb grains, new epitaxial relationships have been found: GaSb ( 111 ) ||Si ( 11 1 ¯ ) and GaSb [ 11 2 ¯ ] ||Si [ 1 1 ¯ 0 ] , GaSb ( 113 ) ||Si ( 11 1 ¯ ) and GaSb [ 1 1 ¯ 0 ] ||Si [ 1 1 ¯ 0 ] , and GaSb ( 11 1 ¯ ) ||Si ( 002 ) and GaSb [ 1 1 ¯ 0 ] ||Si [ 1 1 ¯ 0 ] .
Bulletin of Materials Science, 1995
Undoped and Te-doped gallium antimonide (GaSb) layers have been grown on GaSb bulk substrates by the liquid phase epitaxial technique from Ga-rich and Sb-rich melts. The nucleation morphology of the grown layers has been studied as a function of growth temperature and substrale orientation. MOS structures have been fabricated on the epilayers to evaluate the native defect content in the grown layers from the C-V characteristics. Layers grown from antimony rich melts always exhibit p-type conductivity. In contrast, a type conversion from p-to n~ was observed in layers grown from gallium rich melts below 400 C. The electron mobility of undoped n-type layers grown from Ga-rich melts and tellurium doped layers grown from Sb-and Ga-rich solutions has been evaluated.
physica status solidi (b), 2016
An investigation was performed on the heteroepitaxial growth of In x Ga 1-x Sb on GaSb/Si(111)-√3 Â √3-Ga substrate following a two-step growth method. The buffer layer flux ratio of Ga and Sb has been controlled precisely to grow a high-quality GaSb layer without twins, whereas the ratio of In and Ga varied for epitaxial In x Ga 1-x Sb layers. The growth conditions during film deposition were kept the same for growth with and without a high-quality buffer layer of GaSb. The ratio x ranges from 0.75 to 0.9 in steps of 0.05. To analyze and compare the growth, reflection high energy electron diffraction (RHEED), scanning electron microscopy (SEM) images, and X-ray diffraction (XRD) have been performed and studied. It was found that the high-quality (HQ) GaSb buffer layer is necessary to decrease twins in the growing InGaSb layer.