Materials growth and band offset determination of Al2O3/In0.15Ga0.85Sb/GaSb/GaAs heterostructure grown by metalorganic chemical vapor deposition (original) (raw)
Applied Physics Express, 2017
The growth of high-quality In 0.28 Ga 0.72 Sb epilayer on an AlSb/GaSb/GaAs heterostructure by metalorganic chemical vapor deposition is demonstrated. The In 0.28 Ga 0.72 Sb epilayer has a fully relaxed surface roughness of >1.0 nm and a low threading dislocation density of >6.2 ' 10 6 cm %2. The valence band offset (VBO) of 3.11 eV and conduction band offset (CBO) of 3.21 eV for an Al 2 O 3 /In 0.28 Ga 0.72 Sb interface extracted from X-ray photoemission spectroscopy data highlight its suitability for use in single-channel InGaSb-based complementary metal-oxide-semiconductor (CMOS) applications. The type-I straddling gap of an In 0.28 Ga 0.72 Sb/AlSb heterojunction with a VBO of 0.47 eV and CBO of 0.65 eV is also sufficient to prevent both electron and hole leakage currents in CMOS devices.
Effect of growth temperature on InGaSb metamorphic layers and the fabrication of InGaSb p-i-n diodes
Journal of Vacuum Science Technology B Microelectronics and Nanometer Structures, 2008
Metamorphic growth of In 0.15 Ga 0.85 Sb on a GaSb substrate is reported using In x Ga 1−x Sb buffer layers compositionally graded in steps of x = 0.03. All layers were grown using gas source molecular beam epitaxy with a fixed Sb flux providing an excess group-V overpressure. The growth temperature was varied from 450 to 540°C. X-ray diffraction analysis was used to determine the effect of growth temperature on relaxation and residual strain. As the growth temperature is increased, cross-sectional transmission electron microscopy ͑TEM͒ shows that the number of dislocations threading through the metamorphic layer are reduced. Plan-view TEM yields misfit dislocation density around 10 8 cm −2 and from atomic force microscopy, the surface roughness is ϳ1 nm. Both surface roughness and dislocation density improves with higher growth temperature. Finally, p-i-n homojunction diodes of various sizes on metamorphic layers were demonstrated.
Physica Status Solidi (a), 1994
Sb films are grown on GaSb(100) and GaAs(100) substrates and the film defects are investigated by using chemical etching and optical microscopic techniques. A new wet chemical etching method that revealed film defects in thin MBE GaSb and Ino,,,Gao &b films is evaluated, and it is found that a hot HCI solution under illumination is most effective in revealing the defects of the thin MBE films. Dislocations and stacking faults, which are related to the substrate material selected, substrate quality, substrate surface preparation, and the insertion of a buffer layer are clearly observed. In particular, in the growth of Ino,,,Gao,,,Sb, the huge lattice mismatch between the Ino, ,Ga,,,,Sb and GaAs substrate causes severe dislocations, as well as stacking faults. Meanwhile, the AlSb buffer layer is able to eliminate stacking faults and reduce dislocations in Ino.17Gao,83Sb films and thereby improve the electrical characteristics of the Ino,,,Gao,,,Sb film.
Nanotechnology, 2014
Using a step-graded (SG) buffer structure via metal-organic chemical vapor deposition, we demonstrate a high suitability of In0.5Ga0.5As epitaxial layers on a GaAs substrate for electronic device application. Taking advantage of the technique's precise control, we were able to increase the number of SG layers to achieve a fairly low dislocation density (∼10(6) cm(-2)), while keeping each individual SG layer slightly exceeding the critical thickness (∼80 nm) for strain relaxation. This met the demanded but contradictory requirements, and even offered excellent scalability by lowering the whole buffer structure down to 2.3 μm. This scalability overwhelmingly excels the forefront studies. The effects of the SG misfit strain on the crystal quality and surface morphology of In0.5Ga0.5As epitaxial layers were carefully investigated, and were correlated to threading dislocation (TD) blocking mechanisms. From microstructural analyses, TDs can be blocked effectively through self-annihila...
A strain relief mode at interface of GaSb/GaAs grown by metalorganic chemical vapor deposition
Applied Physics Letters, 2011
Epitaxial growth of Ti3SiC2 thin films with basal planes parallel or orthogonal to the surface on α-SiC Appl. Phys. Lett. 101, 021606 (2012) Recombination mechanisms in heteroepitaxial non-polar InGaN/GaN quantum wells J. Appl. Phys. 112, 013534 (2012) Growth and characterizations of semipolar (112) InN J. Appl. Phys. 112, 013530 Epitaxial two dimensional aluminum films on silicon (111) by ultra-fast thermal deposition J. Appl. Phys. 111, 124320 Atomic behavior of carbon atoms on a Si removed 3C-SiC (111) surface during the early stage of epitaxial graphene growth
Applied Physics Express, 2009
In situ real-time X-ray diffraction measurements during In 0:12 Ga 0:88 As/GaAs(001) epitaxial growth are performed for the first time to understand the strain relaxation mechanisms in a lattice-mismatched system. The high resolution reciprocal space maps of 004 diffraction obtained at interval of 6.2 nm thickness enable transient behavior of residual strain and crystal quality to be observed simultaneously as a function of InGaAs film thickness. From the evolution of these data, five thickness ranges with different relaxation processes and these transition points are determined quantitatively, and the dominant dislocation behavior in each phase is deduced.
MBE growth and characterisation of AlxGa1−xSb layers on GaSb substrates
Journal of Crystal Growth, 1999
V Ga \V Sb layers on GaSb(0 0 1) have been grown by molecular beam epitaxy (MBE) and characterised by high-resolution X-ray di!raction (HRXRD) and secondary ion mass spectrometry (SIMS) measurements. The antimonide layers inevitably contain residual As amounting to 0.5 mol%. This cannot be avoided when growing the "lms in a MBE apparatus previously used for GaAs growth, at least for the applied growth temperature of 4703C. Segregation processes of Ga from the GaSb bu!er layer and Al from the heteroepitaxial layer into the layers above are detected by SIMS. Since monomeric Sb forms metallic "lms on the sample surface, the exposure to a monomeric Sb #ux below 3703C should be avoided in order to obtain a clean surface. The composition of the 150 nm thick quaternary Al V Ga \V As W Sb \W layers was determined with high precision.
Misfit dislocations in InGaAs/InP mbe single heterostructures
Journal of Crystal Growth, 1986
Misfit dislocations in In 1_~Ga~As/InPsingle heterostructures grown by molecular beam epitaxy were studied by X-ray topography, cathodoluminescence and chemical etching. It was found that they are parallel to the KilO> directions lying on the (001) growth plane, that they are 600 type with Burgers vector at 45°to the (001) plane and that they are driven by the misfit stress into the InP substrate up to a depth of a few lsm. The growth conditions, i.e. the layer thickness and lattice mismatch, under which misfit dislocation-free heterostructures can be obtained were determined. Finally, the correlation between cross hatch patterns on the epilayer surface and misfit dislocations was studied.
Misfit dislocation reduction in InGaAs epilayers grown on porous GaAs substrates
Applied Surface Science, 2014
Elastic accommodation of heteroepitaxial layers beyond their critical thickness is crucial for the reduction of misfit dislocations. One approach is to utilize substrate engineering in order to delay plastic relaxation. In this work, pore networks were introduced electrochemically in GaAs substrates in order to modify their mechanical responses. In x Ga 1−x As epilayers with nominal indium contents up to x = 0.20 were then deposited by MOVPE, and were compared to similar epilayers grown on nonporous GaAs. Strain relaxation and defect introduction were studied by TEM observations, x-ray diffraction, and photoluminescence measurements. It was found that the porous substrates acted to reduce the density of misfit dislocations, thereby increasing the epilayer critical thickness. The InGaAs epilayers retained a significantly higher amount of elastic strain compared to ones grown on nonporous GaAs. The onset of plasticity was mediated by the pores, which acted as nucleation sites for 60 • dislocations that glided toward the interface.
Influence of interface dislocations on surface kinetics during epitaxial growth of InGaAs
Applied Surface Science, 1998
The correlation between surface striations and misfit dislocations at the interface has been studied on InxGa I ~As single layers (x < 0.25), as a function of the growth parameters (substrate temperature and deposition rate), by means of atomic force and transmission electron microscopies. It is concluded that both features may be initially linked by mechanical causes (elastic displacement fields), but eventually evolve in a different way due to the surface kinetic effects. The range of growth conditions for an optimum surface quality is determined. A simplified treatment of the diffusion equation, in which the effect of the surface on the dislocation stress field is included, has allowed an estimation of the effective mean free path between collisions for the group III adatoms in the range of a few A.
Journal of Crystal Growth
GaSb p-in photodiodes were grown on GaAs and Si, using interfacial misfit arrays, and on native GaSb. For the samples grown on GaAs and Si, high-resolution transmission electron microscopy images revealed interface atomic periodicities in agreement with atomistic modeling. Surface defect densities of ~1 × 10 8 cm −2 were measured for both samples. Atomic force microscopy scans revealed surface roughnesses of around 1.6 nm, compared with 0.5 nm for the sample grown on native GaSb. Dark current and spectral response measurements were used to study the electrical and optoelectronic properties of all three samples.
Applied Physics Express, 2018
A GaSb epilayer is grown on a GaAs/Si(001) epitaxial substrate via metalorganic chemical vapor deposition. High-resolution transmission electron microscopy micrographs and high-resolution X-ray reciprocal space mapping indicate an entirely relaxed interfacial misfit (IMF) array GaSb epilayer. The valence-band offset and conduction-band offset of the Al 2 O 3 /GaSb/GaAs/Si structure are estimated to be 2.39 and 3.65 eV, respectively. The fabricated Al 2 O 3 /p-GaSb/GaAs/Si MOS capacitors exhibited good capacitance-voltage characteristics with a small accumulation frequency dispersion of approximately 1.05% per decade. These results imply that the GaSb epilayer grown on the GaAs/Si platform in the IMF mode can be used for future complementary metal-oxide semiconductor applications.
Applied Physics Letters, 2002
Strain evolution during In 0.2 Ga 0.8 As/GaAs ͑001͒ growth by molecular beam epitaxy has been monitored in real time. We have detected that three main relaxation stages, related to different mechanisms, take place during growth, and we have obtained the thickness range where those mechanisms are active. The in situ measured relaxation behavior in the plastic stages has been described by means of a simple equilibrium model that takes into account dislocations generation and interaction between them. The excellent agreement between the experimental data and the model allows us to determine the value of the formation energy per unit length of a misfit dislocation and the extent of the interaction between dislocations in this material system.
Journal of Applied Physics, 1993
Thick (--3 IBM) films of In,Ga,-As grown on GaAs( 100) substrates, across the whole composition range, have been examined by transmission electron microscopy and double-crystal x-ray diffmction. The results were compared with the observed growth mode of the material determined by in situ reflection high-energy electron diffraction in the molecular beam epitaxy growth system. The quality of the material degraded noticeably for compositions up to X-0.5 associated with an increased density of dislocations and stacking faults. In contrast, improvements in quality as x approached 1.0 were correlated with the introduction of an increasingly more regular array of edge dislocations. 1731
Applied Physics Letters, 2017
We report epitaxial growth of GaSb nano-ridge structures and planar thin films on V-groove patterned Si (001) substrates by leveraging the aspect ratio trapping technique. GaSb was deposited on {111} Si facets of the V-shaped trenches using metal-organic chemical vapor deposition with a 7 nm GaAs growth initiation layer. Transmission electron microscopy analysis reveals the critical role of the GaAs layer in providing a U-shaped surface for subsequent GaSb epitaxy. A network of misfit dislocations was uncovered at the GaSb/GaAs hetero-interface. We studied the evolution of the lattice relaxation as the growth progresses from closely pitched GaSb ridges to coalesced thin films using x-ray diffraction. The omega rocking curve full-width-at-half-maximum of the resultant GaSb thin film is among the lowest values reported by molecular beam epitaxy, substantiating the effectiveness of the defect necking mechanism. These results thus present promising opportunities for the heterogeneous integration of devices based on 6.1 A ˚family compound semiconductors.
Nanoscale research …, 2009
We report structural analysis of completely relaxed GaSb epitaxial layers deposited monolithically on GaAs substrates using interfacial misfit (IMF) array growth mode. Unlike the traditional tetragonal distortion approach, strain due to the lattice mismatch is spontaneously relieved at the heterointerface in this growth. The complete and instantaneous strain relief at the GaSb/GaAs interface is achieved by the formation of a two-dimensional Lomer dislocation network comprising of pure-edge (90°) dislocations along both [110] and [1-10]. In the present analysis, structural properties of GaSb deposited using both IMF and non-IMF growths are compared. Moiré fringe patterns along with X-ray diffraction measure the long-range uniformity and strain relaxation of the IMF samples. The proof for the existence of the IMF array and low threading dislocation density is provided with the help of transmission electron micrographs for the GaSb epitaxial layer. Our results indicate that the IMF-grown GaSb is completely (98.5%) relaxed with very low density of threading dislocations (105 cm−2), while GaSb deposited using non-IMF growth is compressively strained and has a higher average density of threading dislocations (>109 cm−2).
1994
Strain release and dislocation distribution in InGaAs/ GaAs double heterostructures, step-graded and lineargraded buffer layers have been studied. A higher misfit dislocation density at the inner interface between the InGaAs layer and the substrate was found in all the samples. This corresponded to a strain release of the inner ternary layers much larger than predicted by equilibrium theories. The residual parallel strain of the external layers as a function of their thickness was found to follow a curve approximately of slope-0.5, in agreement with previous investigations on single InGaAs layers. This result has been interpreted as evidence that the elastic energy per unit interface area remains constant during the epilayer growth. The presence of numerous single and multiple dislocation loops inside the substrate was attributed to the strain relaxation occurring through dislocation multiplication via Frank-Read sources activated during the growth. A comparison with InGaAs/ GaAs step-graded and linear-graded heterostructures is also shown and briefly discussed. Finally, lattice plane tilts between epilayers and substrates have been found due to the imbalance in the linear density of misfit dislocations with opposite component of the Burgers vector, b .l eff, perpendicular to the interface.