In Situ Measurements of Stress Relaxation During Strained Layer Heteroepitaxy

1999 ◽  
Vol 583 ◽  
Author(s):  
E. Chason ◽  
J. Yin ◽  
K. Tetz ◽  
R. Beresford ◽  
L. B. Freund ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Stress Relaxation ◽  
Epitaxial Growth ◽  
Real Time ◽  
Misfit Strain ◽  
Misfit Stress ◽  
Relaxation Kinetics ◽  
Substrate Interface ◽  
Temperature Relaxation

AbstractWe present real-time measurements of stress relaxation kinetics during epitaxial growth obtained using a wafer-curvature-based technique optimized for in situ studies. Depending on the temperature and misfit strain, different mechanisms of stress relaxation are observed. In heterolayers of InGaAs grown on GaAs (001) substrates, relaxation occurs by a dislocationmediated mechanism. In SiGe layers grown on Si (001) substrates at elevated temperature, relaxation occurs by the formation of islands on the surface. These islands elastically relax misfit stress without the introduction of dislocations at the island-substrate interface.

Real-Time in Situ Monitoring of Defect Evolution at Widegap II-VI/GaAs Heterointerfaces during Epitaxial Growth

1993 ◽  
Vol 324 ◽  
Author(s):  
C.M. Rouleau ◽  
R.M. Park
Keyword(s):  
Epitaxial Growth ◽  
Real Time ◽  
Laser Light ◽  
Scattered Light ◽  
Normal Incidence ◽  
Light Signal ◽  
In Situ Monitoring ◽  
Laser Probe ◽  
Dislocation Formation

AbstractWe report the real-time in situ observation of heterointerface dislocation formation during the growth of lattice-mismatched widegap II-VI/GaAs heterostructures. Such observations were made by employing a near-normal incidence HeNe laser probe during epitaxial growth which generated both a laser reflection interferometry (LRI) signal as well as an elastically scattered laser light (ELLS) signal. We believe that the scattered light signal is generated at the II-VI/GaAs heterointerface based on the observation of a π phase difference between the LRI and the ELLS signals which were monitored simultaneously. We suggest, therefore, that the observed ELLS signal is a consequence of dislocation formation at the heterointerface which occurs due to plastic deformation in lattice-mismatched systems.

Real-time in situ x-ray diffraction as a method to control epitaxial growth

2003 ◽  
Vol 82 (26) ◽  
pp. 4684-4686 ◽  
Author(s):  
A. S. Bader ◽  
W. Faschinger ◽  
C. Schumacher ◽  
J. Geurts ◽  
L. W. Molenkamp ◽  
...  
Keyword(s):  
Epitaxial Growth ◽  
Real Time ◽  
X Ray Diffraction ◽  
X Ray

Direct Observation of Stress Relaxation Process in 4H-SiC Homoepitaxial Layers via In Situ Synchrotron X-Ray Topography

2018 ◽  
Vol 924 ◽  
pp. 176-179
Author(s):  
Jian Qiu Guo ◽  
Yu Yang ◽  
Balaji Raghothamachar ◽  
Michael Dudley ◽  
Swetlana Weit ◽  
...  
Keyword(s):  
Stress Relaxation ◽  
Relaxation Process ◽  
Direct Observation ◽  
Misfit Strain ◽  
Interfacial Dislocation ◽  
Concentration Difference ◽  
X Ray ◽  
High Temperature Heat Treatment ◽  
Basal Plane Dislocation

During 4H silicon carbide (4H-SiC) homoepitaxy and post-growth processes, the development of stress relaxation has been observed, in which interfacial dislocations (IDs) are formed at the epilayer/substrate interface, relaxing the misfit strain induced by the nitrogen doping concentration difference between the epilayer and substrate. It is widely believed that an interfacial dislocation is created by the glide of a mobile segment of a basal plane dislocation (BPD) in the substrate or epilayer towards the interface, leaving a trailing edge component right at the interface. However, direct observation of such mechanisms has not been made in SiC before. In this work, we present an in situ study of the stress relaxation process, in which a specimen cut from a commercial 4H-SiC homoepitaxial wafer undergoes the stress relaxation process during a high-temperature heat treatment while sequential synchrotron white beam X-ray topographs were recorded simultaneously. Based on the dynamic observation of this process, it can be concluded that thermal stress plays a role in the relaxation process while the increased misfit strain at elevated temperature most likely drives the formation of an interfacial dislocation.

Mechanism of misfit stress relaxation during epitaxial growth of GaN on porous SiC substrates

2006 ◽  
Vol 32 (12) ◽  
pp. 1011-1013
Author(s):  
M. G. Mynbaeva ◽  
O. V. Konstantinov ◽  
K. D. Mynbaev ◽  
A. E. Romanov ◽  
A. A. Sitnikova
Keyword(s):  
Stress Relaxation ◽  
Epitaxial Growth ◽  
Misfit Stress ◽  
Porous Sic

scholarly journals Параметрическая модель спектров оптических постоянных Hg-=SUB=-1-x-=/SUB=-Cd-=SUB=-x-=/SUB=-Te и определение состава соединения

2020 ◽  
Vol 128 (12) ◽  
pp. 1815
Author(s):  
В.А. Швец ◽  
Д.В. Марин ◽  
В.Г. Ремесник ◽  
И.А. Азаров ◽  
М.В. Якушев ◽  
...  
Keyword(s):  
Epitaxial Growth ◽  
Real Time ◽  
Empirical Data ◽  
Optical Constants ◽  
Parametric Model

A parametric model describing the spectra of the optical constants Hg1-xCdxTe n( lam) and k(lam) for x values in the range from 0.2 to 0.4 is presented. The Model is based on empirical data measured in situ during epitaxial growth of the compound layers. Variants of using the obtained model for determining the composition of MCT in situ in real time are considered. A method for determining the composition based on spectral ellipsometric measurements is proposed, which provides an accuracy no worse than (del)x=±0.0035.

In Situ Diagnostics Of Epitaxial Growth Using Reflectance-Difference

1990 ◽  
Vol 204 ◽  
Author(s):  
Lars Samuelson ◽  
Jan JÖnsson ◽  
Gert Paulsson
Keyword(s):  
Epitaxial Growth ◽  
Real Time ◽  
Catalytic Effect ◽  
Atomic Layer ◽  
Initial Slope ◽  
Special Significance ◽  
Real Time Control ◽  
Time Control ◽  
Surface Changes

ABSTRACTOptical in situ methods are becoming of increasing importance for studies of the mechanisms of growth and for real-time control of surface processes involved in epitaxial growth. We present data from studies, using the reflectance-difference (RD) method, of different processes related to epitaxial growth of GaAs (001) from arsine (AsH3) and from triethylgallium (TEG). RD studies make it possible to follow how the near-equilibrium, Ga-rich, configuration of the GaAs (001) surface changes with temperature and we show how the transformation to this state can be followed from As-saturated as well as from Ga-saturated surfaces. From the initial slope of the RD-transient, corresponding to the AsH3 reaction with a Ga-stabilized surface, the temperature dependence of the catalytic effect of this surface on the decomposition of arsine is measured. Of special significance for an atomic layer epitaxial process (ALE) is the demonstration of a self-limiting reaction of TEG. This process can be followed as the surface modifies itself from a state obtained by exposure to excess TEG to the near-equilibrium Ga-terminated reconstruction. Finally, we demonstrate how pulsing sequences for the realization of ALE can be followed and controlled in real time using RD as a diagnostic tool.

Real-Time Observation of Ti Silicide Epitaxial Islands Growth with the Photoelectron Emission Microscopy

1998 ◽  
Vol 533 ◽  
Author(s):  
W. Yang ◽  
H. Ade ◽  
R. J. Nemanich
Keyword(s):  
Elevated Temperature ◽  
Real Time ◽  
Electron Emission ◽  
Room Temperature ◽  
Island Growth ◽  
Photoelectron Emission ◽  
Emission Microscopy ◽  
Time Observation ◽  
Real Time Observation

AbstractThe formation of nanoscale Ti silicide islands was observed by Photo-electron emission microscopy (PEEM). The islands were prepared by deposition of an ultrathin Ti (3–12ML) on Si(001) at room temperature and at an elevated temperature of 950°C. The island formation was initiated by in situ annealing to 1150° C. It was observed that initially Ti silicide islands form while longer annealing indicates some islands move and coalesce with other islands. Most of the islands are similar in size and have relatively uniform separation. Also, it was shown that for continued Ti deposition at a temperature of 950°C, the density of islands did not increase. However, islands grew together when their perimeter lines touch each other. The results are described in terms of island growth processes of coalescence and ripening.

Modelling of Precipitation Kinetics with Simultanous Stress Relaxation

2006 ◽  
Vol 979 ◽  
Author(s):  
Franz Dieter Fischer ◽  
Jiri Svoboda ◽  
Ernst Gamsjäger ◽  
Ernst Kozeschnik ◽  
Bernhard Sonderegger
Keyword(s):  
Stress Relaxation ◽  
Growth Kinetics ◽  
Binary Systems ◽  
Misfit Strain ◽  
Internal Stresses ◽  
Precipitation Kinetics ◽  
Misfit Stress ◽  
New Model ◽  
Precipitate Growth ◽  
The Matrix

AbstractMisfit strain connected with the formation of large internal stresses may drastically influence the precipitation kinetics. A new model for the simultaneous precipitate growth and misfit stress relaxation in binary systems has been developed based on the idea that the internal stresses are relaxed by generation or annihilation of vacancies at the matrix/precipitate interface. The model is applied to the Fe-C system by considering the growth of the cementite precipitate in the ferritic matrix. The influence of the stress relaxation on the precipitate growth kinetics is demonstrated.

Direct Observations of the Epitaxial Growth of Sputtered Ag on Si

1973 ◽  
Vol 31 ◽  
pp. 122-123
Author(s):  
J. S. Maa ◽  
Thos. E. Hutchinson
Keyword(s):  
Epitaxial Growth ◽  
Film Growth ◽  
Ion Beam ◽  
Ion Beam Sputtering ◽  
Microscopy Technique ◽  
Direct Observations ◽  
In Situ Electron Microscopy ◽  
Beam Sputtering ◽  
The Subject

The growth of Ag films deposited on various substrate materials such as MoS2, mica, graphite, and MgO has been investigated extensively using the in situ electron microscopy technique. The three stages of film growth, namely, the nucleation, growth of islands followed by liquid-like coalescence have been observed in both the vacuum vapor deposited and ion beam sputtered thin films. The mechanisms of nucleation and growth of silver films formed by ion beam sputtering on the (111) plane of silicon comprise the subject of this paper. A novel mode of epitaxial growth is observed to that seen previously.The experimental arrangement for the present study is the same as previous experiments, and the preparation procedure for obtaining thin silicon substrate is presented in a separate paper.

Probing the Dynamic Self-Assembly Behaviour of Photoswitchable Wormlike Micelles in Real Time

2018 ◽  
Author(s):  
Elaine A. Kelly ◽  
Judith E. Houston ◽  
Rachel Evans
Keyword(s):  
Real Time ◽  
Absorption Spectroscopy ◽  
Self Assembly ◽  
Uv Light ◽  
Wormlike Micelles ◽  
Tetraethylene Glycol ◽  
Light Illumination ◽  
First Time ◽  
Dependent Processes

Understanding the dynamic self-assembly behaviour of azobenzene photosurfactants (AzoPS) is crucial to advance their use in controlled release applications such as<i></i>drug delivery and micellar catalysis. Currently, their behaviour in the equilibrium <i>cis-</i>and <i>trans</i>-photostationary states is more widely understood than during the photoisomerisation process itself. Here, we investigate the time-dependent self-assembly of the different photoisomers of a model neutral AzoPS, <a>tetraethylene glycol mono(4′,4-octyloxy,octyl-azobenzene) </a>(C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>) using small-angle neutron scattering (SANS). We show that the incorporation of <i>in-situ</i>UV-Vis absorption spectroscopy with SANS allows the scattering profile, and hence micelle shape, to be correlated with the extent of photoisomerisation in real-time. It was observed that C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>could switch between wormlike micelles (<i>trans</i>native state) and fractal aggregates (under UV light), with changes in the self-assembled structure arising concurrently with changes in the absorption spectrum. Wormlike micelles could be recovered within 60 seconds of blue light illumination. To the best of our knowledge, this is the first time the degree of AzoPS photoisomerisation has been tracked <i>in</i><i>-situ</i>through combined UV-Vis absorption spectroscopy-SANS measurements. This technique could be widely used to gain mechanistic and kinetic insights into light-dependent processes that are reliant on self-assembly.

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