Nonhydrostatic Stress Effects on Boron Diffusion in SI

1997 ◽  
Vol 469 ◽  
Author(s):  
Michael J. Aziz
Keyword(s):  
Hydrostatic Pressure ◽  
Hydrostatic Stress ◽  
Diffusion Mechanism ◽  
Biaxial Stress ◽  
Extended Defects ◽  
Boron Diffusion ◽  
Stress Effects ◽  
Atomistic Calculations ◽  
Strained Films

ABSTRACTThe thermodynamics of diffusion under hydrostatic pressure and nonhydrostatic stress is developed for single crystals free of extended defects and is applied to the case of boron diffusion in silicon. The thermodynamic relationships obtained permit the direct comparison of hydrostatic and biaxial stress experiments and of atomistic calculations under hydrostatic stress. Assuming various values for the anisotropy in the migration strain, a currently unknown parameter, comparison is made between various measurements under hydrostatic pressure and nonhydrostatic stress, and various atomistic calculations of the volumetrics of B and Si diffusion by an interstitial-based mechanism. An independent determination of the anisotropy of the migration strain would permit a parameter-free determination of the predominant diffusion mechanism and would permit the prediction of the ratio of the diffusivity normal to the free surface to the diffusivity parallel to the surface for biaxially strained films. Procedures for measuring and calculating the anisotropy in the migration strain are described.

scholarly journals Effect Of Pressure On Boron Diffusion In Silicon

1996 ◽  
Vol 442 ◽  
Author(s):  
Yuechao Zhao ◽  
Michael J. Aziz ◽  
Salman Mitha ◽  
David Schiferl
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Diffusion Mechanism ◽  
Boron Diffusion ◽  
Effect Of Pressure ◽  
Self Diffusion ◽  
Pressure Medium ◽  
Atomistic Calculations ◽  
Fluid Argon ◽  
Homoepitaxial Layers ◽  
Strained Films

AbstractWe are studying the effect of pressure on boron diffusion in silicon in order to better understand the nature of the point defects responsible for diffusion. Si homoepitaxial layers deltadoped with boron were grown using molecular beam epitaxy. Diffusion anneals were performed in a high temperature diamond anvil cell using fluid argon as a pressure medium. Diffusivities were deduced from B concentration-depth profiles measured with using secondary ion mass spectrometry. Preliminary results indicate that pressure enhances B diffusion in Si at 850 °C, characterized by an average activation volume of -0.125±0.02 times the atomic volume, and thus appear consistent with an interstitial-based diffusion mechanism. Results are compared with previous hydrostatic-pressure studies, with results in biaxially strained films, and with atomistic calculations of activation volumes for self diffusion.

scholarly journals Dopant Diffusion in Si1-xGex Thin Films: Effect of Epitaxial Stress

2006 ◽  
Vol 249 ◽  
pp. 135-142
Author(s):  
Alain Portavoce ◽  
Isabelle Berbezier ◽  
Antoine Ronda ◽  
Patrick Gas ◽  
J.S. Christensen ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
Defect Formation ◽  
Activation Volume ◽  
Diffusion Mechanism ◽  
Lattice Diffusion ◽  
Biaxial Stress ◽  
Chemical Effect ◽  
Stress Effect ◽  
Dopant Diffusion ◽  
Effect Change

We have investigated the lattice diffusion of B and Sb by means of molecular beam epitaxy in Si1−xGex (x < 0.2) layers grown on Si(001) substrate. Using Si1−xGex relaxed buffers we were able to differentiate the chemical effect (change in the Ge composition) as opposite to the biaxial stress effect (due to the epitaxy on Si) on dopant diffusion. B diffusion follows a behavior opposite to Sb diffusion versus Ge composition and biaxial stress. These results are explained in view of the difference of diffusion mechanism between B (interstitials) and Sb (vacancies). We also show that dopant diffusion follows contrasting behaviors under biaxial pressure and hydrostatic pressure, and that the activation volume of dopant diffusion is of opposite sign for biaxial pressure and for hydrostatic pressure. This is explained using a formalism based on the extra work done by the system for diffusion under pressure, concluding that for biaxial stress the activation volume depends mainly on the relaxation volume linked to the defect formation.

Direct determination of the self-diffusion mechanism in bccβ-titanium

1989 ◽  
Vol 39 (8) ◽  
pp. 5025-5034 ◽  
Author(s):  
G. Vogl ◽  
W. Petry ◽  
Th. Flottmann ◽  
A. Heiming
Keyword(s):  
Diffusion Mechanism ◽  
Direct Determination ◽  
The Self ◽  
Self Diffusion

Biaxial stress effects on magnetization perpendicular to the stress plane

1995 ◽  
Vol 31 (6) ◽  
pp. 3665-3667 ◽  
Author(s):  
M.J. Sablik ◽  
H. Kwun ◽  
G.L. Burkhardt ◽  
R.A. Langman
Keyword(s):  
Biaxial Stress ◽  
Stress Effects ◽  
Stress Plane

Enhancement of solid-state reaction rates by non-hydrostatic stress effects on polycrystalline diffusion kinetics

2010 ◽  
Vol 95 (10) ◽  
pp. 1399-1407 ◽  
Author(s):  
L. M. Keller ◽  
L. C. Gotze ◽  
E. Rybacki ◽  
G. Dresen ◽  
R. Abart
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Hydrostatic Stress ◽  
Reaction Rates ◽  
Diffusion Kinetics ◽  
Stress Effects

Activation Volume Measurements

1971 ◽  
Vol 26 (2) ◽  
pp. 291-299 ◽  
Author(s):  
Michele Beyeler ◽  
David Lazarus
Keyword(s):  
Sodium Chloride ◽  
Hydrostatic Pressure ◽  
Ionic Conductivity ◽  
Activation Volume ◽  
Tracer Diffusion ◽  
Accurate Temperature ◽  
Volume Measurements ◽  
Accurate Temperature Control ◽  
Effect Of Hydrostatic Pressure

Abstract The determination of the activation volume of diffusion is one of the best methods for the in­vestigation of the relaxation of atoms or ions around defects. This paper discusses two experimental techniques for the determination of the activation volume for diffusion, by studying the effect of hydrostatic pressure on tracer diffusion and on ionic conductivity. Such experiments require a very clean hydrostatic pressure environment, accurate temperature control and measurement, and well defined specimen geometry. The difficulties encountered during such experiments are discussed. Results are given for the activation volumes of diffusion in beryllium and in sodium chloride.

scholarly journals Cruciform specimens for the determination of crack growth behaviour in biaxial stress fields: calculation of K-factors

2019 ◽  
Vol 300 ◽  
pp. 11008
Author(s):  
Carl H. Wolf ◽  
Andreas Burgold ◽  
Sebastian Henkel ◽  
Meinhard Kuna ◽  
Horst Biermann
Keyword(s):  
Crack Growth ◽  
Steel Specimen ◽  
Biaxial Stress ◽  
Transmission Factor ◽  
Crack Growth Behaviour ◽  
Aluminum Specimen ◽  
Small Influence ◽  
Simplified Calculation ◽  
Crack Paths

The aim of this study is to propose a simplified calculation of the Mode I stress intensity factor K for the cruciform specimen design proposed by Brown and Miller. To calculate K, both cracks have to grow with a similar crack growth rate and the crack paths of the two single cracks with the length a should also be similar. The calculations are carried out on an aluminum specimen and a steel specimen. For all load cases and materials, the stresses resulting from the forces are first considered. It was found that the elastic constants E and ν have only a small influence of less than 3 %. In addition, the coupling between the forces of the load axes, which should be minimized by the slotted arms, is considered. Furthermore K-factors are calculated by FE for different crack lengths. These K-values together with the transmission factor allow to find a K-factor formula for cruciform specimens, which is based on the prescribed forces. Finally, the results of the FE calculation of the exact straight crack paths were compared to experimentally determined crack paths.

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