Growth and transport properties of relaxed epilayers of InAs on GaAs (original) (raw)
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Journal of Vacuum Science & Technology B, 2008
InAs and high indium concentration InGaAs have very high electron mobilities and saturation velocities. Using them as the metal oxide semiconductor field effect transistor ͑MOSFET͒ channel materials is a very promising way to keep improving the integrated circuit chip performance beyond Moore's law. One major obstacle is the growth of these high mobility channel materials on lattice-mismatched substratcs. In this work, we studied the molecular beam epitaxy growth of InAs, In 0.8 Al 0.2 As, and In 0.8 Ga 0.2 As on lattice-mismatched GaAs substrate using a thin indium-rich InAs wetting layer. Reflection high energy electron diffraction and atomic force microscopy were used to optimize the growth conditions. A surface roughness of ϳ0.5 nm rms was obtained for InAs layers. A new MOSFET structure with In 0.8 Ga 0.2 As channel and In 0.8 Al 0.2 As buffer layer was also demonstrated. High mobility depletion mode MOSFET characteristics were demonstrated.
Growth of InAs on GaAs (001) by migration-enhanced epitaxy
SPIE Proceedings, 1990
AlGaAs/InGaAs modulation-doped field-effect transistors with a nominally (InAs)2(GaAs)-channel grown by migration-enhanced epitaxy exhibit better luminescent and device properties than those with a random alloy In'" 4 ,Ga 6 s channel grown by molecular-beam epitaxy (MBE). We have proposed nad applied a new kinetic model, which includes both group-IlI alkyl and group-V species in the surface chemical reactions, to tl.r growth of GaAs, GaSb, and InAs by metalorganic MBE or chemical-beam epitaxy (CBE). We have also set up a gas-source MBE system with elemental group-Ill and doping sources as well as arsine and phosphine. We used the group-Vlimited growth mode to determine in situ the exact values of V/Ill atomic ratios during growth of GaP, InP, AlP, and GaAs. X-ray studies of an InAlAs/InP superlattice indicates ,the existence of a P/As-intermixed,strained interface. , .' ''. _;.,, 14. SUBJECT TERMS IS. NUMBER OF PAGES AlGaAs/InGaAs, InP, GaP, GaAs, InAlAs/InP ll MODFET, migration-enhanced epitaxy (KEE), MBE, GaSb, 16.PRICE coot MOMBE, CBE, GSMBE, growth kinetics, strain 17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19. SECURITY CLASSIFICATION 20. LIMITATION OF ABSTRACT OF REPORT OF THIS PAGE. OF ABSTRACT UNCLASSIFIED UNCLASSIFIED UNCLASSIFIED ________ NIN 7S40-01.2BO.SSOO Standard Form 298 (Rtv 2-99) ftwO £000 Sid 119'S Table of Contents 1. Molecular beam epitaxial growth and characterization of pseudomorphic modulation-doped field effect transistors ..
Growth and coalescence evolution of InAs on GaAs by molecular beam epitaxy
Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 2002
InAs layers, grown on GaAs substrates using molecular beam epitaxy, has been systematically investigated. Through the observation of pyrometer readings, it was found that the transition of both the growth mode and the surface morphology of InAs layers are strongly dependent on the As 4 /In flux ratio and the substrate temperature. Cross-sectional transmission electron microscopy images showed that effective reduction in defect density resulting from the InAs/GaAs interface was achieved for InAs layers with a thickness of only 1.5 m.
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.
Materials Science and Engineering: B, 1994
We report a study, based on high resolution X-ray diffraction and photoluminescence (PL) measurements, of In segregation in InAs/GaAs quantum wells (QWs) 1 monolayer thick, grown by molecular beam epitaxy (MBE) and atomic layer molecular beam epitaxy (ALMBE), at different temperatures. The In content in the structures is evaluated by simulations of diffraction profiles, carried out according to the dynamical theory of X-ray diffraction. To study the segregation, we propose a new approach based on a suitable choice of the diffraction geometry. This approach allows us to deduce a value of 5.5 A for the In segregation length in MBE structures prepared at 480 and 420 °C, and in the ALMBE structure prepared at 360 °C, while a slightly larger value (6.5 A) is found in the ALMBE QWs grown at 460 °C. PL results on the same QWs can be interpreted in terms of a growth-temperature-dependent segregation. Our results show that the effects of segregation decrease with decreasing growth temperature and that, at a given temperature, segregation is more effective in the ALMBE structures than in the MBE counterparts.
Growth of InAs on Si substrates at low temperatures using metalorganic vapor phase epitaxy
Journal of Crystal Growth, 2008
The growth behavior of InAs on Si using metalorganic vapor phase epitaxy (MOVPE) was studied. The large lattice mismatch of InAs to Si, $12%, results in island formation under typical MOVPE growth conditions, which prevents the development of the thin coherent films of InAs needed for high-speed device applications. The growth of InAs at low temperature is expected to lead to rapid nucleation and low surface mobility, resulting in the formation of a coherent film at low thicknesses. This study explored the growth behavior of InAs on Si at low temperatures, i.e. o350 1C and varying V/III ratio. InAs films were grown on {1 0 0}-, {111}-and {2 11}-oriented Si substrates using trimethyl indium, tertiary butyl arsine and AsH 3. Small islands ranging from 15 to 30 nm form on the samples at growth temperatures o325 1C. Subsequent annealing of this thin layer at 600 1C for 5 min leads to island coarsening. High-resolution X-ray diffraction, atomic force microscopy and scanning electron microscopy were used to characterize InAs layer grown on Si.
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.
physica status solidi (RRL) – Rapid Research Letters, 2020
The A III B V binary compounds with approximately 6.1 Å lattice constant are currently under the great interest of both research groups [1] and manufacturers of advanced electronics. [2] There are many reasons for the 6.1 Å family popularity. The most important is the extraordinary flexibility for bandgap engineering achieved in the infrared energy range via compound alloying and the reduction of dimensionality. [3] Therefore, a wide range of high-speed and low-power devices can be realized, taking the advantage of GaAs, InSb, and InAs properties. [4] In particular, a special attention is devoted to ultrathin layers and low-dimensional objects made of InAs, for example, quantum dots, [5] nanowires, [6] topological insulators, [7] and quantum wells. [8] Indium arsenide forms an active layer in various optoelectronic devices, such as quantum cascade lasers [9] or infrared detectors. [10] Current application of InAs also includes Hall sensor devices [11,12] and high-electron-mobility transistors (HEMTs) [13,14] in which transport properties are extremely important. As a result, more and more detailed knowledge about this compound and its interfaces is still needed for the design of complex structures meant for applications. Especially, the precise description of electrical carrier transport in multilayered structures is a key factor in the device fabrication. Here, the great progress has been made, in which the possibility of separated-conductivity-channels observation plays an important role. The separation of different contributions to the electrical conductivity has become possible through a technique known as the mobility spectrum analysis (MSA). [15] This method is especially interesting for the characterization of valence bands (VBs) because the interpretation of measurement data obtained for p-type channels is much more demanding than for data collected for transport via normally separated conduction band. Therefore, there is a relatively small number of literature reports, where multichannel p-conduction is analyzed and, for example, light-hole effective mass m lh or hole mobility μ h versus temperature are presented. [16,17] In this article, we present the detailed study on electronic carrier transport in highly doped p-type InAs layer grown on the GaAs semi-insulating substrate. Structure uniformity has been analyzed using the secondary-ion mass spectrometry (SIMS) and highly symmetrical four-terminal electrical devices have been fabricated using the photolithography (PL) technique. Resistance and Hall effect have been measured in the temperature range of 1.5-300 K at magnetic fields up to 16 T. The high quality of obtained data enabled us to apply the very precise variant of MSA method, the so-called high-resolution quantitative mobility spectrum analysis (HR-QMSA). [15] We identified up
Journal of Alloys and Compounds, 2012
InAs layers were grown with and without bismuth flow by atmospheric pressure metalorganic vapor phase epitaxy on exactly oriented, 2 • and 10 • misoriented (1 0 0) GaAs substrates. Structural analysis was carried out using high resolution X-ray diffraction. Without bismuth flow, only InAs layers grown on 10 • misoriented substrates exhibit a mosaic structure. Layers grown on exactly oriented and 2 • misoriented substrates show large full widths at half maxima of their diffraction rocking curves. Growing InAs under bismuth flow leads to the reduction of this full width indicating a clear improvement of their structural quality. Particularly for samples grown on 10 • misoriented substrates, a complete disappearance of the mosaic structure was obtained. The crystalline quality improvement is attributed to the contribution of Bi nanodots in relieving strain.