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.

Strain-Free GexSi1−x Layers with Low Threading Dislocation Densities Grown on Si Substrates

1991 ◽  
Vol 220 ◽  
Author(s):  
E. A. Fitzgerald ◽  
Y. H. Xie ◽  
M. L. Green ◽  
D. Brasen ◽  
A. R. Kortan ◽  
...  
Keyword(s):  
Threading Dislocation ◽  
Plan View ◽  
Light Emitting ◽  
Si Substrates ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Electron Beam Induced Current ◽  
Current Densities ◽  
Dimensional Electron Gas ◽  
Compositional Grading

ABSTRACTWe have grown linearly compositionally graded GexSi1−x structures at high temperatures (700–900°C) on Si substrates to form a surface which resembles a GexSi1−x substrate. We have obtained completely relaxed structures with x≤0.50 and threading dislocation densities in the 105cm−2 - 106cm−2 range. Because of the very low threading dislocation densities, the structures appear dislocation free in conventional transmission electron microscopy (TEM) cross-section and plan view. Employing the electron beam induced current technique (EBIC), we were able to consistently measure these low threading dislocation densities. A direct comparison of two x=0.35 films, one graded in Ge content and one uniform in Ge content, shows that compositional grading decreases the dislocation density by a factor of 100–1000. These. higher quality graded buffers have been used as templates for the subsequent growth of InGaP light emitting diodes (LED) and GexSi1−x/Si two-dimensional electron gas (2DEG) structures. Room temperature operation of orange-red LEDs were obtained at current densities of =600A/cm, and mobilities as high as 96,000 cm2/V-s were achieved at 4.2K in the 2DEG structures.

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.

scholarly journals Nano-Ridge Engineering of GaSb for the Integration of InAs/GaSb Heterostructures on 300 mm (001) Si

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 330 ◽  
Author(s):  
Marina Baryshnikova ◽  
Yves Mols ◽  
Yoshiyuki Ishii ◽  
Reynald Alcotte ◽  
Han Han ◽  
...  
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
Defect Density ◽  
Bipolar Transistors ◽  
Monolithic Integration ◽  
Threading Dislocation ◽  
Contrast Imaging ◽  
Si Substrates ◽  
Selective Area ◽  
Transmission Electron ◽  
The Impact

Nano-ridge engineering (NRE) is a novel heteroepitaxial approach for the monolithic integration of lattice-mismatched III-V devices on Si substrates. It has been successfully applied to GaAs for the realization of nano-ridge (NR) laser diodes and heterojunction bipolar transistors on 300 mm Si wafers. In this report we extend NRE to GaSb for the integration of narrow bandgap heterostructures on Si. GaSb is deposited by selective area growth in narrow oxide trenches fabricated on 300 mm Si substrates to reduce the defect density by aspect ratio trapping. The GaSb growth is continued and the NR shape on top of the oxide pattern is manipulated via NRE to achieve a broad (001) NR surface. The impact of different seed layers (GaAs and InAs) on the threading dislocation and planar defect densities in the GaSb NRs is investigated as a function of trench width by using transmission electron microscopy (TEM) as well as electron channeling contrast imaging (ECCI), which provides significantly better defect statistics in comparison to TEM only. An InAs/GaSb multi-layer heterostructure is added on top of an optimized NR structure. The high crystal quality and low defect density emphasize the potential of this monolithic integration approach for infrared optoelectronic devices on 300 mm Si substrates.

The Crystalline Quality of Epitaxial Si Layers Solution Grown on Polycrystalline Si Substrates

1994 ◽  
Vol 358 ◽  
Author(s):  
M. Albrecht ◽  
B. Steiner ◽  
Th. Bergmann ◽  
A. Voigt ◽  
W. Dorsch ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Epitaxial Layer ◽  
Defect Density ◽  
Thin Layers ◽  
Induced Current ◽  
Si Substrates ◽  
Transmission Electron ◽  
Current Transmission ◽  
Electron Beam Induced Current

ABSTRACTWe investigate the crystalline and electrical quality of thin layers epitaxially grown on polycrystalline substrates from metallic solution by the method of electron beam induced current, transmission electron microscopy and etching experiments. We observe a reduced recombination strength of dislocations and small angle grain boundaries, i.e. an improved electrical quality of the epitaxial layer compared to the substrate. The improved quality can be attributed (i) to an altered structure of grain boundaries and dislocations and (ii) to a reduced defect density in the epitaxial layer.

Correlation Between Defect Density and Process Variables In Step-Graded, Relaxed Si0.7Ge0.3 Grown on Si by Rtcvd

1993 ◽  
Vol 303 ◽  
Author(s):  
G. Patrick Watson ◽  
Eugene A. Fitzgerald ◽  
Bahram Jalali ◽  
Ya-Hong Xie ◽  
Bonnie Weir ◽  
...  
Keyword(s):  
Defect Density ◽  
Chemical Vapor ◽  
Dark Spot ◽  
Threading Dislocation ◽  
Dark Line ◽  
Si Substrates ◽  
Transmission Electron ◽  
Threading Dislocation Density ◽  
Line Defects ◽  
Threading Defects

ABSTRACTThe effect of the average grading rate and of the number of incremental Ge alloy steps on the threading dislocation density has been studied in 30% Ge relaxed films formed by rapid thermal chemical vapor deposition (RTCVD) on Si substrates. Electron beam induced current (EBIC) images and transmission electron microscopy (TEM) show that threading defects fall in two categories: individual threading dislocations (dark spot defects), and organized clusters of these threads (pile-ups, or dark line defects). The overall surface defect density must include both categories to properly characterize the material. The lowest defect density, 4 × 105cm−2, was found in specimens grown at an average grading rate of 10% Ge per pm thickness.

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.

Molecular-Beam Epitaxial Growth of GaAs on Si(321)

1988 ◽  
Vol 116 ◽  
Author(s):  
P.N. Uppal ◽  
J.S. Ahearn ◽  
S.W. Duncan
Keyword(s):  
Molecular Beam ◽  
Strain Relaxation ◽  
Stacking Faults ◽  
Dislocation Glide ◽  
Molecular Beam Epitaxial ◽  
Charged Interface ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Gaas Films ◽  
Molecular Beam Epitaxial Growth

AbstractMaterial properties of GaAs films grown on Si(321) substrates using molecular beam epitaxy (MBE) were evaluated and compared to films grown on Si(100) and Si(211). Dislocation densities in the GaAs(321) films, determined using transmission electron microscopy (TEM), were lower than those observed in GaAs(100) and GaAs(211), and the density of stacking faults in GaAs(321) also was quantitatively lower than in GaAs(211). Low-temperature (4.2 K) photoluminescence spectroscopy (PL) indicated that the tensile stress on the GaAs(321) films was greater than that on GaAs(100). These differences are attributed to changes in the strain-relaxation process caused by variations in the number of geometric arrangement of active-dislocation glide systems with different orientations. In addition, Si uptake near the GaAs/Si interface was less than 1/100 of a monolayer in GaAs(321) and 1/4 of a monolayer in GaAs(100). This difference is attributed to the presence of a non-polar (neutral) interface in the (321), whereas the (100) has a polar (charged) interface. MODFET devices with a I-)m gate length exhibited a transconductance of 180–200 ms/mm, comparable to devices on homoepitaxial GaAs(100).

Influence of MBE Growth Conditions on Dislocation Densities of GaAs/Ge Epilayers Grown on Silicon Substrates

1985 ◽  
Vol 43 ◽  
pp. 364-365
Author(s):  
K.M. Hones ◽  
P. Sheldon ◽  
B.G. Yacobi ◽  
A. Mason
Keyword(s):  
High Efficiency ◽  
Lattice Mismatch ◽  
Low Cost ◽  
Growth Conditions ◽  
Nonradiative Recombination ◽  
Device Structure ◽  
Si Substrates ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Dislocation Type

There is increasing interest in growing epitaxial GaAs on Si substrates. Such a device structure would allow low-cost substrates to be used for high-efficiency cascade- junction solar cells. However, high-defect densities may result from the large lattice mismatch (∼4%) between the GaAs epilayer and the silicon substrate. These defects can act as nonradiative recombination centers that can degrade the optical and electrical properties of the epitaxially grown GaAs. For this reason, it is important to optimize epilayer growth conditions in order to minimize resulting dislocation densities. The purpose of this paper is to provide an indication of the quality of the epitaxially grown GaAs layers by using transmission electron microscopy (TEM) to examine dislocation type and density as a function of various growth conditions. In this study an intermediate Ge layer was used to avoid nucleation difficulties observed for GaAs growth directly on Si substrates. GaAs/Ge epilayers were grown by molecular beam epitaxy (MBE) on Si substrates in a manner similar to that described previously.

Defect-Engineered Graded GexSi1-x Buffers on Si (001) with Extreme Low Threading Dislocation Density

1995 ◽  
Vol 378 ◽  
Author(s):  
G. Kissinger ◽  
T. Morgenstern ◽  
G. Morgenstern ◽  
H. B. Erzgräber ◽  
H. Richter
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Atomic Force Microscopy ◽  
Dislocation Density ◽  
Threading Dislocation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Threading Dislocation Density

AbstractStepwise equilibrated graded GexSii-x (x≤0.2) buffers with threading dislocation densities between 102 and 103 cm−2 on the whole area of 4 inch silicon wafers were grown and studied by transmission electron microscopy, defect etching, atomic force microscopy and photoluminescence spectroscopy.

Totally relaxed GexSi1−xlayers with low threading dislocation densities grown on Si substrates

1991 ◽  
Vol 59 (7) ◽  
pp. 811-813 ◽  
Author(s):  
E. A. Fitzgerald ◽  
Y.‐H. Xie ◽  
M. L. Green ◽  
D. Brasen ◽  
A. R. Kortan ◽  
...  
Keyword(s):  
Threading Dislocation ◽  
Si Substrates ◽  
Dislocation Densities
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