Nucleation of misfit dislocations in strained‐layer epitaxy in the GexSi1−x/Si system

1989 ◽  
Vol 7 (4) ◽  
pp. 2580-2585 ◽  
Author(s):  
R. Hull ◽  
J. C. Bean
Keyword(s):  
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.

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

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.

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

Strain Relaxation Mechanisms in Lattice Mismatched Epitaxy

1990 ◽  
Vol 198 ◽  
Author(s):  
R. Hull ◽  
J.C. Bean ◽  
J.M. Bonar ◽  
L. Peticolas
Keyword(s):  
Strain Relaxation ◽  
Epitaxial Layers ◽  
Misfit Dislocations ◽  
Strained Layer ◽  
Device Structures ◽  
Lattice Mismatched Epitaxy

ABSTRACTThe relaxation of strained epitaxial layers by the introduction of misfit dislocations is reviewed. Current theoretical and experimental understanding of the nucleation, propagation and interaction of misfit dislocations are summarized. The ramifications for applicability of strained layer epitaxy to practical device structures are discussed.

Evolution of Surface Roughness of a Strained Epitaxial Film Due to Interface Misfit Dislocations

1993 ◽  
Vol 317 ◽  
Author(s):  
F. Jonsdottir ◽  
L. B. Freund
Keyword(s):  
Surface Roughness ◽  
Surface Diffusion ◽  
Chemical Potential ◽  
Epitaxial Film ◽  
Potential Gradient ◽  
Surface Shape ◽  
Misfit Dislocations ◽  
Chemical Potential Gradient ◽  
Strained Layer

ABSTRACTThe appearance of misfit dislocations at the interface between a strained layer and its substrate induces a nonuniform chemical potential along the surface of the layer. Under the assumption that the resulting chemical potential gradient will drive coherent mass rearrangement by surface diffusion, a model of evolution of surface shape is considered which leads to estimates of the surface roughness induced by this mechanism.

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