scholarly journals Formation of misfit dislocations in strained-layer GaAs/In[sub x]Ga[sub 1−x]As/GaAs heterostructures during postfabrication thermal processing

2003 ◽  
Vol 94 (12) ◽  
pp. 7496 ◽  
Author(s):  
X. W. Liu ◽  
A. A. Hopgood ◽  
B. F. Usher ◽  
H. Wang ◽  
N. St. J. Braithwaite
Keyword(s):  
Thermal Processing ◽  
Misfit Dislocations ◽  
Strained Layer

In situ TEM measurements of the electrical properties of interface dislocations

1992 ◽  
Vol 50 (2) ◽  
pp. 1338-1339
Author(s):  
F. M. Ross ◽  
R. Hull ◽  
D. Bahnck ◽  
J. C. Bean ◽  
L. J. Peticolas ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Electronic Device ◽  
In Situ Tem ◽  
Device Performance ◽  
Misfit Dislocations ◽  
Electrical Characteristics ◽  
Strained Layer ◽  
Transmission Electron ◽  
Interfacial Dislocations

We describe an investigation of the electrical properties of interfacial dislocations in strained layer heterostructures. We have been measuring both the structural and electrical characteristics of strained layer p-n junction diodes simultaneously in a transmission electron microscope, enabling us to correlate changes in the electrical characteristics of a device with the formation of dislocations.The presence of dislocations within an electronic device is known to degrade the device performance. This degradation is of increasing significance in the design and processing of novel strained layer devices which may require layer thicknesses above the critical thickness (hc), where it is energetically favourable for the layers to relax by the formation of misfit dislocations at the strained interfaces. In order to quantify how device performance is affected when relaxation occurs we have therefore been investigating the electrical properties of dislocations at the p-n junction in Si/GeSi diodes.

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.

Edge-type misfit dislocations produced by thermal processing of pre-relaxed InxGa1−xAs/GaAs heterostructures

2000 ◽  
Vol 88 (10) ◽  
pp. 5975-5980 ◽  
Author(s):  
X. W. Liu ◽  
A. A. Hopgood ◽  
B. F. Usher ◽  
H. Wang ◽  
N. S. Braithwaite
Keyword(s):  
Thermal Processing ◽  
Misfit Dislocations ◽  
Edge Type

The Creation of Misfit Dislocations; A Study of InGaAs Alloys on GaAs Substrates

1990 ◽  
Vol 202 ◽  
Author(s):  
Peter J Goodhew ◽  
Philip Kightley
Keyword(s):  
Measurement Error ◽  
Buffer Layer ◽  
Interface Plane ◽  
Misfit Dislocations ◽  
Strained Layer ◽  
Gaas Substrates ◽  
Angle Point ◽  
Point Of Intersection ◽  
Edge Dislocations ◽  
Line Direction

ABSTRACTGrowth onto vicinal substrates causes 60° misfit dislocations to adopt line directions away from <110> in order for them to maintain their presence within the substrate to strained layer interface. Observations show that for the growth of an on-axis [001]wafer the dislocations have a line direction, within measurement error, exactly [110] or [-110] and two sets of orthogonal dislocations are generated. When grown onto a wafer that is cut off-axis toward [010] four sets of dislocations are generated. The two sets of dislocations in each direction converge to form low angle intersections from which edge dislocations are formed. These edge dislocations can become very long by the glide out of the interface plane of the component 60° dislocations. This ‘zipping-up’ to form the edge components only occurs in one direction from the low angle point of intersection and the edge segments are exclusively generated in the buffer layer. Their density and penetration are a function of thickness and composition of the mismatched epilayer. The mechanisms by which the dislocations adopt line directions away from <110> and why they zip-up from the intersection in only one direction are discussed.

Rapid Thermal Processing of Buried Sil−xGex Strained Layers; Photoluminescence Decay and Misfit Dislocation Generation.

1990 ◽  
Vol 198 ◽  
Author(s):  
D.C. Houghton ◽  
N.L. Rowell
Keyword(s):  
Quantum Wells ◽  
Misfit Dislocation ◽  
Thermal Processing ◽  
Internal Quantum Efficiency ◽  
Dislocation Nucleation ◽  
Multiple Quantum ◽  
Misfit Dislocations ◽  
Dislocation Generation ◽  
Strained Layers ◽  
Wide Range

ABSTRACTThe thermal constraints for device processing imposed by strain relaxation have been determined for a wide range of Si-Ge strained heterostructures. Misfit dislocation densities and glide velocities in uncapped Sil-xGex alloy layers, Sil-xGex single and multiple quantum wells have been measured using defect etching and TEM for a range of anneal temperatures (450°C-1000°C) and anneal times (5s-2000s). The decay of an intense photoluminescence peak (∼ 10% internal quantum efficiency ) from buried Si1-xGex strained layers has been correlated with the generation of misfit dislocations in adjacent Sil-xGex /Si interfaces. The misfit dislocation nucleation rate and glide velocity for all geometries and alloy compositions (0<x<0.25) were found to be thermally activated processes with activation energies of (2.5±0.2)eV and (2.3-0.65x)eV, respectively. The time-temperature regime available for thermal processing is mapped out as a function of dislocation density using a new kinetic model.

Formation of misfit dislocations during growth of InxGa1-xAs/GaAs strained-layer heterostructures

1999 ◽  
Vol 14 (12) ◽  
pp. 1154-1160 ◽  
Author(s):  
X W Liu ◽  
A A Hopgood ◽  
B F Usher ◽  
H Wang ◽  
N St J Braithwaite
Keyword(s):  
Misfit Dislocations ◽  
Strained Layer

Rapid Thermal Processing for Strained-Layer Semiconductor Devices

1993 ◽  
Vol 303 ◽  
Author(s):  
John C. Zolper ◽  
David R. Myers
Keyword(s):  
Band Structure ◽  
Semiconductor Lasers ◽  
Thermal Processing ◽  
Rapid Thermal Processing ◽  
Strained Layer ◽  
Layer Structures ◽  
Thermodynamic Limits ◽  
The Stability ◽  
Mismatched Heteroepitaxy ◽  
Strained Layer Superlattices

ABSTRACTStrained-layer semiconductors have revolutionized modern heterostructure devices by exploiting the modification of semiconductor band structure associated with the coherent strain of lattice-mismatched heteroepitaxy. The modified band structure improves transport of holes in heterostructures and enhances the operation of semiconductor lasers. Strainedlayer epitaxy also can create materials whose band gaps match wavelengths (e. g. 1.06 μm and 1.32 μm) not attainable in ternary epitaxial systems lattice matched to binary substrates. Other benefits arise from metallurgical effects of modulated strain fields on dislocations.Lattice mismatched epitaxial layers that exceed the limits of equilibrium thermodynamics will degrade under sufficient thermal processing by converting the as-grown coherent epitaxy into a network of strain-relieving dislocations. After presenting the effects of strain on band structure, we describe the stability criterion for rapid-thermal processing of strained-layer structures and the effects of exceeding the thermodynamic limits. Finally, device results are reviewed for structures that benefit from high temperature processing of strained-layer superlattices.

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