Misfit Dislocation Nucleation and Interactions at GexSi1-x/Si Interfaces

1989 ◽  
Vol 160 ◽  
Author(s):  
D.D. Perovic ◽  
G.C. Weatherly ◽  
D.C. Houghton
Keyword(s):  
Misfit Dislocation ◽  
Dominant Role ◽  
Strain Relaxation ◽  
Dislocation Nucleation ◽  
Interfacial Dislocation ◽  
Dislocation Generation ◽  
Transmission Electron ◽  
Metastable Structures ◽  
Nucleation Mechanisms ◽  
Generation Mechanisms

AbstractIn the study of elastic strain relaxation in semiconductor heterostructures, a number of misfit dislocation generation mechanisms have been suggested to account for the high interfacial dislocation density observed in these almost defect-free crystals. Several MBE-grown GexSi1-x/Si heterostructures, both in the as-grown and annealed condition have been studied using transmission electron microscopy. The results indicate that some of the popular theories of dislocation generation are less important or not applicable based on both theoretical and experimental considerations. Specifically, it will be shown that: (i) heterogeneous sources play a dominant role in the nucleation mechanisms, (ii) the strain relaxation behaviour during MBE growth may be different from that observed in metastable structures annealed after growth and (iii) the Hagen-S trunk multiplication mechanism is inoperative under most conditions in this system.

Strain Relaxation at Low Misfits: Dislocation Injection vs. Surface Roughening

1995 ◽  
Vol 399 ◽  
Author(s):  
D.D. Perovic ◽  
B. Bahierathan ◽  
D.C. Houghton ◽  
H. Lafontaine ◽  
J.-M. Baribeau
Keyword(s):  
Misfit Dislocation ◽  
Strain Relaxation ◽  
Relaxation Mechanism ◽  
Theoretical Description ◽  
Dislocation Nucleation ◽  
Surface Roughening ◽  
X Ray Diffraction ◽  
Dislocation Generation ◽  
Force Microscopy ◽  
Atomic Force

ABSTRACTTwo competing strain relaxation mechanisms, namely misfit dislocation generation and surface roughening, have been extensively studied using the GexSi1-x/Si (x< 0.5) system as an example. A predictive model has been developed which accurately describes the nature of misfit dislocation nucleation and growth under non-equilibrium conditions. Using optical and electron microscopy, coupled with a refined theoretical description of dislocation nucleation, it is shown that strain relieving dislocations are readily generated at low misfits with a characteristic activation energy barrier regardless of the growth technique employed (i.e. MBE, RTCVD and UHVCVD). Secondly we have studied the alternative elastic strain relaxation mechanism involving surface undulation; x-ray diffraction, electron and atomic force microscopy have been used to characterize GexSi1-x/Si (x<0.5) structures grown by UHVCVD and MBE at relatively higher temperatures. A theoretical model has been used to model the critical thickness for surface wave generation. The conditions governing the interplay between dislocation formation and surface buckling are described in terms of a "morphological instability diagram".

Kinetic Barriers to Strain Relaxation in GexSi1-x/Si Epitaxy

1989 ◽  
Vol 160 ◽  
Author(s):  
R. Hull ◽  
J.C. Bean
Keyword(s):  
Relaxation Process ◽  
Misfit Dislocation ◽  
Strain Relaxation ◽  
Dislocation Nucleation ◽  
Transmission Electron ◽  
Structure Geometry ◽  
Si Epitaxy ◽  
Annealing Experiments ◽  
Kinetic Barriers

AbstractWe discuss the kinetic barriers to misfit dislocation nucleation, propagation and interaction in lattice-mismatched GexSi1-x/Si epitaxy. Experimental real-time observations of the strain relaxation process via in-situ annealing experiments in a transmission electron microscope enable each of these processes to be separately studied. Quantitative parameters defining misfit dislocation processes may be derived; these are found to be highly dependent upon the structure geometry. The approximations involved in extending these measurements to a description of the relaxation process during growth are described in detail.

Experimental and Theoretical Analysis of Strain Relaxation in GexSi1-x/Si(100) Heteroepitaxy

1989 ◽  
Vol 148 ◽  
Author(s):  
R. Hull ◽  
J.C. Bean
Keyword(s):  
Misfit Dislocation ◽  
Strain Relaxation ◽  
Dislocation Nucleation ◽  
Fundamental Parameters ◽  
Interaction Processes ◽  
Transmission Electron ◽  
Wide Range ◽  
Relaxation Measurements ◽  
Good Agreement

ABSTRACTBy analyzing in-situ strain relaxation measurements of GexSi1-x/Si(100) epitaxy in a Transmission Electron Microscope, we are able to quantify the fundamental parameters which describe strain energy relaxation via misfit dislocation introduction. Quantitative descriptions of misfit dislocation nucleation, propagation and interaction processes are derived. The numerical parameters obtained from these experiments are then incorporated into a predictive theoretical model of strain relaxation whichrelies only upon experimentally measured quantities. Good agreement between experiment and theory is obtained over a wide range of data.

Development of Cross-Hatch Morphology During Growth of Lattice Mismatched Layers

2001 ◽  
Vol 673 ◽  
Author(s):  
A. Maxwell Andrews ◽  
J.S. Speck ◽  
A.E. Romanov ◽  
M. Bobeth ◽  
W. Pompe
Keyword(s):  
Misfit Dislocation ◽  
Film Growth ◽  
Strain Relaxation ◽  
Dislocation Generation ◽  
Force Microscopy ◽  
Step Flow ◽  
Atomic Force ◽  
Subsequent Step ◽  
Step Flow Growth ◽  
Lateral Scale

ABSTRACTAn approach is developed for understanding the cross-hatch morphology in lattice mismatched heteroepitaxial film growth. It is demonstrated that both strain relaxation associated with misfit dislocation formation and subsequent step elimination (e.g. by step-flow growth) are responsible for the appearance of nanoscopic surface height undulations (0.1-10 nm) on a mesoscopic (∼100 nm) lateral scale. The results of Monte Carlo simulations for dislocation- assisted strain relaxation and subsequent film growth predict the development of cross-hatch patterns with a characteristic surface undulation magnitude ∼50 Å in an approximately 70% strain relaxed In0.25Ga0.75As layers. The model is supported by atomic force microscopy (AFM) observations of cross-hatch morphology in the same composition samples grown well beyond the critical thickness for misfit dislocation generation.

Semiconductor Superlattices: Order and Disorder

1987 ◽  
Vol 93 ◽  
Author(s):  
R. Hull ◽  
J. E. Turner ◽  
A. Fischer-Colbrie ◽  
Alice E. Whitea ◽  
K. T. Short ◽  
...  
Keyword(s):  
Lattice Mismatch ◽  
Strain Relaxation ◽  
Multilayer Structures ◽  
Two Dimensional ◽  
Semiconductor Alloys ◽  
Dislocation Generation ◽  
Growth Interface ◽  
Order And Disorder ◽  
Metastable Structures ◽  
Si Ion Implantation

ABSTRACTWe review and discuss the main structural phenomena inherent in epitaxial multilayer semiconductor growth: lattice mismatch, misfit dislocation generation, two-dimensional vs. threedimensional growth, interface abruptness and planarity and the local atomic structure of semiconductor alloys. The prevalence of metastable structures, often a function of crystal growth temperature, is discussed. We also investigate the effect of Si ion implantation and subsequent rapid thermal annealing of AlGaAs/GaAs and InGaAs/GaAs multilayer structures, with reference to strain relaxation, layer planarity and enhanced Al, In and Si diffusion.

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.

Comparison of Growth and Strain Relaxation of Si/Ge Superlattices Under Compressive and Tensile Strain Field

1991 ◽  
Vol 220 ◽  
Author(s):  
Werner Wegscheider ◽  
Karl Eberl ◽  
Gerhard Abstreiter ◽  
Hans Cerva ◽  
Helmut Oppolzer
Keyword(s):  
Growth Parameters ◽  
Strain Relaxation ◽  
Dislocation Nucleation ◽  
Misfit Dislocations ◽  
Partial Dislocations ◽  
Transmission Electron ◽  
Short Period ◽  
Low Energy Electron ◽  
Superlattice Period

ABSTRACTOptimization of growth parameters of short period Si/Ge superlattices (SLs) has been achieved via in situ low-energy electron diffraction (LEED) and Auger electron spectroscopy (AES) measurements during homo- and heteroepitaxy on Si (001) and Ge (001) substrates. Transmission electron microscopy (TEM) reveals that pseudomorphic SimGe12-m (m = 9 and 3 for growth on Si and Ge, respectively) SLs with extended planar layering can be prepared almost defect-free by a modified molecular beam epitaxy (MBE) technique. Whereas the SLs on Ge can be deposited at a constant substrate temperature, high-quality growth on Si demands for temperature variations of more than 100°C within one superlattice period. Strain relaxation of these SLs with increasing number of periods has been directly compared by means of TEM. For the compressively strained structures grown on Si we found misfit dislocations of the type 60° (a/2)<110>. Under opposite strain conditions i.e. for growth on Ge, strain relief occurs only by microtwin formation through successive glide of 90° (a/6)<211> Shockley partial dislocations. This is consistent with a calculation of the activation energy for both cases based on a homogeneous dislocation nucleation model.

Onset of Misfit Dislocation Generation in As-Grown and Annealed Sil-XGex/Si Films

1988 ◽  
Vol 130 ◽  
Author(s):  
M. P. Scott ◽  
S. S. Laderman ◽  
T. I. Kamins ◽  
S. J. Rosner ◽  
K. Nauka ◽  
...  
Keyword(s):  
Misfit Dislocation ◽  
Chemical Vapor ◽  
Misfit Dislocations ◽  
Epitaxial Silicon ◽  
Dislocation Generation ◽  
Transmission Electron ◽  
Vapor Deposition Technique ◽  
Si Films ◽  
Reaction Processing ◽  
Thermal Stability Of

AbstractX-ray topography and transmission electron microscopy were used to quantify misfit-dislocation spacings in as-grown Si1-xGex films formed by Limited Reaction Processing (LRP), which is a chemical vapor deposition technique. These analysis techniques were also used to study dislocation formation during annealing of material grown by both LRP and by molecular beam epitaxy (MBE). The thickness at which misfit dislocations first appear in as-grown material was similar for both growth techniques. The thermal stability of capped and uncapped films was also investigated after rapid thermal annealing in the range of 625 to 1000°C. Significantly fewer misfit dislocations were observed in samples containing an epitaxial silicon cap. Some differences in the number of misfit dislocation generated in CVD and MBE films were observed after annealing uncapped layers at temperatures between 625 and 825°C.

Strain Relaxation Mechanisms in He+-Implanted and Annealed Si1−xGex Layers on Si(001) Substrates

2001 ◽  
Vol 686 ◽  
Author(s):  
S.H. Christiansen ◽  
P.M. Mooney ◽  
J.O. Chu ◽  
A. Grill
Keyword(s):  
Misfit Dislocation ◽  
Strain Relaxation ◽  
Three Dimensional ◽  
Dislocation Network ◽  
Misfit Dislocations ◽  
Dislocation Loops ◽  
X Ray Diffraction ◽  
Si Substrate ◽  
Transmission Electron ◽  
Microscopy Techniques

AbstractStrain relaxation in He+-implanted and annealed Si(001)/Si1−xGex heterostructures was investigated using transmission electron microscopy techniques and x-ray diffraction. Depending on the implant conditions, bubbles and/or platelets form below the Si/Si1−xGex interface upon annealing and act as nucleation sources for dislocation loops. The dislocation loops extend to the interface and form a misfit dislocation network there, resulting in relaxation of 30-80% of the strain in layers as thin as 100-300 nm. When bubbles form close to the interface, dislocations nucleate by a climb loop mechanism. When smaller bubbles form deeper in the Si substrate an irregular three-dimensional dislocation network forms below the interface resulting in an irregular misfit dislocation network at the interface. When platelets form deeper in the Si substrate, prismatic punching of dislocation loops is observed and dislocation reactions of misfit dislocations at the interface result in Lomer dislocation formation.

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