MBE Growth of Low Dislocation and High Mobility GaAs-on-Si

1986 ◽  
Vol 67 ◽  
Author(s):  
Jhang Woo Lee
Keyword(s):  
Layer Structure ◽  
High Mobility ◽  
Gaas Layer ◽  
Buffer Layers ◽  
Misfit Dislocations ◽  
Si Substrates ◽  
Molecular Beam Epitaxial ◽  
Transmission Electron ◽  
Low Dislocation Density ◽  
Molecular Beam Epitaxial Growth

ABSTRACTData is presented on the optimization of several molecular beam epitaxial growth processes to provide low dislocation density and high mobility GaAs single crystals on (100) Si wafers. The substrate tilt angle, the growth temperature, and the first buffer layer structure, were investigated Tor this purpose. Using Hall measurements the GaAs layers grown on 2 or 3-degree tilt (100) Si showed consistently high mobilities which are equivalent to the homoepitaxial GaAs mobility. Transmission electron microscopy (TEM) revealed that on tilted (100) Si substrates most of the misfit dislocations were confined within the first 50 Å GaAs layer by forming a type of edge dislocation at the Si surface step edges. Also low temperature grown buffer layers always gave better morphologies and lower etch pit densities while keeping the high mobilities on overgrown GaAs layers.

Reduction of Defect Density in Heteroepitaxial GexSi1-x Grown on Patterned Si Substrates

1989 ◽  
Vol 160 ◽  
Author(s):  
E.A. Fitzgerald ◽  
Y.-H. Xie ◽  
J. Michel ◽  
P.E. Freeland ◽  
B.E. Weir
Keyword(s):  
Defect Density ◽  
Threading Dislocation ◽  
Patterned Substrate ◽  
Si Substrates ◽  
Molecular Beam Epitaxial ◽  
Etch Pit ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Electron Beam Induced Current ◽  
Molecular Beam Epitaxial Growth

AbstractWe have investigated the molecular beam epitaxial growth of GexSi1-x on small growth areas patterned in Si substrates. Electron beam induced current, etch-pit density measurements, transmission electron microscopy, and photoluminescence were used to compare dislocation densities in GexSi1-x on patterned and unpattemed substrates. We find a dramatic reduction in both misfit and threading dislocation densities for the patterned substrate growth. Our results also show that dislocation introduction is dominated by heterogeneous nucleation.

Molecular Beam Epitaxial Growth and Characterization of InSb and InAsxSb1−x

1990 ◽  
Vol 198 ◽  
Author(s):  
P.N. Uppal ◽  
D.M. Gill ◽  
R. Herring
Keyword(s):  
Tensile Stress ◽  
Hall Effect ◽  
X Ray Diffraction ◽  
Si Substrates ◽  
Molecular Beam Epitaxial ◽  
Gaas On Si ◽  
Transmission Electron ◽  
Hall Effect Measurements ◽  
Molecular Beam Epitaxial Growth ◽  
Alloy Segregation

ABSTRACTLayers of InSb and InAsxSb1-x were grown on GaAs and GaAs on Si substrates and then characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM) to determine the epilayer quality. Hall-effect measurements and photoluminescence (PL) were also performed. Single-crystal XRD indicated that the 5-μm InSb layers grown on GaAs had a peak full width at half maximum (FWHM) of 120 arc sec for the (004) reflection. Planar TEM of a 7-μm-thick InSb layer on GaAs(001) indicated a dislocation density of 2 x 106 cm−2 at the top of the layer. Hall effect measurements of an undoped 3.5-μm-thick InSb on semi-insulating GaAs indicated an electron density of 3.7 x 1016 cm−3 at 300K and a mobility of 45,000 cm2 / V-sec. At 77K these values were 2.7 x 1016 cm−3 and 49,200 cm2 / V-sec, respectively. The composition of the InAsxSb1-x was a function of the growth temperature and the As2/In ratio for both Sb2 and Sb4. The XRD (004) peak FWHM increased with the x value, indicating a deterioration in material quality. This may be caused by alloy segregation in InAsxSb1-x. The peak FWHM rapidly increases from x=0.1 to x=0.3 and then its value drops, indicating that the quality of the layers improved. InSb layers displayed a strong PL whereas the PL for the InAs0.5Sb0.5 layers was very weak. We also grew InSb and InAsxSb1-x layers on GaAs on Si. Optical transmission measurements on InSb indicated that the layers were under tensile stress. We believe this tensile stress could be used to lower the bandgap of InAsxSb1-x layers to provide longer cut-off wavelengths for infrared detectors.

The Effect of Substrate Misorientation on the Evolution of Surface Morphology in Epitaxially Grown CaF2/Si(111) Heterostructures

1995 ◽  
Vol 399 ◽  
Author(s):  
B. M. Kim ◽  
S. R. Soss ◽  
R. M. Overney ◽  
L. J. Schowalter
Keyword(s):  
Surface Morphology ◽  
High Energy ◽  
Ex Situ ◽  
Atomic Step ◽  
Misfit Dislocations ◽  
Si Substrates ◽  
Molecular Beam Epitaxial ◽  
Molecular Beam Epitaxial Growth ◽  
Miscut Angle ◽  
Step Edges

ABSTRACTWe have studied the effect of substrate misorientation on the evolution of surface morphology in lattice-mismatched heterostructures for molecular beam epitaxial growth of a thin insulator (CaF2) on vicinal Si(111) surfaces with in-situ reflection high energy electron diffraction (RHEED) and ex-situ atomic force microscopy (AFM). At a substrate temperature of 770 °C, CaF2 growth is initiated by the formation of a reacted CaF layer followed by the complete overgrowth of an additional CaF2 monolayer (ml). However, CaF2 growth beyond these two ml depends on the degree of miscut of the Si substrate. On Si substrates tilted toward the [112] by a miscut angle ≥ 0.5°, the atomic step edges on the Si surface bunch together forming flat terraces that are ∼200 nm wide. In this case, the CaF2 growth beyond 2 ml proceeds by the nucleation and lateral propagation of thick CaF2 islands (whose height is determined by the step bunches) along the bunched step edges to eventually form a complete overlayer. For CaF2 films grown on substrates with a miscut angle < 0.5°, the CaF2 layer remains relatively uniform without the formation of thick islands. With further deposition, evidence for a dense network of misfit dislocations is observed on the surface of the CaF2 film.

Molecular Beam Epitaxial Growth of ZnSe Layers on GaAs and Si Substrates

2000 ◽  
Vol 220 (1) ◽  
pp. 99-109 ◽  
Author(s):  
M. López-López ◽  
V.H. Méndez-García ◽  
M. Meléndez-Lira ◽  
J. Luyo-Alvarado ◽  
M. Tamura ◽  
...  
Keyword(s):  
Epitaxial Growth ◽  
Molecular Beam ◽  
Si Substrates ◽  
Molecular Beam Epitaxial ◽  
Molecular Beam Epitaxial Growth

Molecular Beam Epitaxial Growth and Characterization of GaAs Films on Thin Si Substrates

1998 ◽  
Vol 37 (Part 1, No. 1) ◽  
pp. 39-44 ◽  
Author(s):  
Kenzo Maehashi ◽  
Hisao Nakashima ◽  
Frank Bertram ◽  
Peter Veit ◽  
Jürgen Christen
Keyword(s):  
Epitaxial Growth ◽  
Molecular Beam ◽  
Si Substrates ◽  
Molecular Beam Epitaxial ◽  
Gaas Films ◽  
Molecular Beam Epitaxial Growth

scholarly journals The Structure of GaAs/Si(211) Heteroepitaxial Layers

1987 ◽  
Vol 91 ◽  
Author(s):  
Zuzanna Liliental-Weber ◽  
E.R. Weber ◽  
J. Washburn ◽  
T.Y. Liu ◽  
H. Kroemer
Keyword(s):  
Buffer Layer ◽  
Surface Preparation ◽  
Gaas Layer ◽  
Misfit Dislocations ◽  
Strained Layer ◽  
Si Substrates ◽  
Density Of Dislocations ◽  
Gaas Buffer Layer ◽  
Graded Layers ◽  
Strained Layer Superlattices

ABSTRACTGallium arsenide films grown on (211)Si by molecular-beam epitaxy have been investigated using transmission electron microscopy. The main defects observed in the alloy were of misfit dislocations, stacking faults, and microtwin lamellas. Silicon surface preparation was found to play an important role on the density of defects formed at the Si/GaAs interface.Two different types of strained-layer superlattices, InGaAs/InGaP and InGaAs/GaAs, were applied either directly to the Si substrate, to a graded layer (GaP-InGaP), or to a GaAs buffer layer to stop the defect propagation into the GaAs films. Applying InGaAs/GaAs instead of InGaAs/InGaP was found to be more effective in blocking defect propagation. In all cases of strained-layer superlattices investigated, dislocation propagation was stopped primarily at the top interface between the superlattice package and GaAs. Graded layers and unstrained AlGaAs/GaAs superlattices did not significantly block dislocations propagating from the interface with Si. Growing of a 50 nm GaAs buffer layer at 505°C followed by 10 strained-layer superlattices of InGaAs/GaAs (5 nm each) resulted in the lowest dislocation density in the GaAs layer (∼;5×l07/cm2) among the structures investigated. This value is comparable to the recently reported density of dislocations in the GaAs layers grown on (100)Si substrates [8]. Applying three sets of the same strained layersdecreased the density of dislocations an additional ∼2/3 times.

MO-CVD GaAs Grown by Direct Deposition on Si

1987 ◽  
Vol 91 ◽  
Author(s):  
S. M. Vernon ◽  
S. J. Pearton ◽  
J. M. Gibson ◽  
R. Caruso ◽  
C. R. Abernathy ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Gaas Layer ◽  
Threading Dislocation ◽  
X Ray Diffraction ◽  
Si Substrates ◽  
Transmission Electron ◽  
Activation Data ◽  
Threading Dislocation Density ◽  
Donor Activity

ABSTRACTGaAs layers were grown directly on misoriented (2° off (100)→[011]) Si substrates by Metalorganic Chemical Vapor Deposition. The threading dislocation density at the surface of 4 μm thick layers was typically 108cm−2, as determined by both preferential etching and transmission electron microscopy. Rapid thermal annealing (900°C, 10s) improved the crystalline quality of the GaAs near the heterointerface while allowing no detectable Si diffusion into this layer. Two deep electron traps were observed in the undoped GaAs, but were present at a low concentration (∼ 1013 cm−3 ). The (400) x-ray diffraction peak width from the GaAs was significantly reduced with increasing GaAs layer thickness, indicating improved material quality. This is supported by Si implant activation data, which shows higher net donor activity in thicker layers.

Molecular Beam Epitaxial Growth of (Al,Ga)As Tilted Superlattices on Vicinal GaAs (110)

1991 ◽  
Vol 237 ◽  
Author(s):  
Mohan Krishnamurthy ◽  
M. Wassermeier ◽  
H. Weman ◽  
J. L. Merz ◽  
P. M. Petroffa
Keyword(s):  
Quantum Wells ◽  
Molecular Beam ◽  
Growth Conditions ◽  
Vicinal Surface ◽  
Vicinal Surfaces ◽  
Island Growth ◽  
Quantum Well Structures ◽  
Molecular Beam Epitaxial ◽  
Transmission Electron ◽  
Molecular Beam Epitaxial Growth

ABSTRACTA study of the molecular beam epitaxial (MBE) growth on singular and vicinal (110) surfaces of GaAs is presented. Quantum well structures and tilted superlattices (TSL) were grown on substrates misoriented 0.5°-2° towards the nearest [010] and [111]A azimuths at growth temperatures ranging from 450° C to 600° C under different growth conditions. The structures were characterized by Nomarski optical microscopy, transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy.Two types of faceting were observed on the surfaces. The structures grown at temperatures above 540°C and As beam fluxes below l×10-5 torr showed V-shaped facets pointing in the [001] direction and are attributed to As deficient island growth. Lower temperatures and higher As beam fluxes lead to surfaces with microfacets that are elongated along the respective step directions on the vicinal surface and are due to step bunching during growth. Their density and height decrease with decreasing vicinal angle and they disappear on the singular (110) surface. The photoluminescence of the GaAs quantum wells grown on these samples is redshifted with respect to that of the quantum wells grown on the flat surface. This is being ascribed to the fact that on the vicinal surface, the recombination takes place at the facets where the quantum wells are wider.The contrast in the TEM images of the TSL show for the samples misoriented towards [010] that the lateral segregation to the step edges on this surface is appreciable. The TSL spacing and the tilt however show that during growth the vicinal surfaces tend towards a surface with smaller miscut.

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