Intrinsic Point Defects and Diffusion Processes in Silicon

1983 ◽  
Vol 31 ◽  
Author(s):  
T. Y. Tan
Keyword(s):  
Point Defects ◽  
Thermal Equilibrium ◽  
Diffusion Processes ◽  
Equilibrium Concentration ◽  
Surface Oxidation ◽  
Self Diffusion ◽  
Equilibrium Concentrations ◽  
And Diffusion

ABSTRACTThis paper reviews recent progress in understanding the role of vacancies (V) and self-interstitials (I) in self and impurity diffusion in Si. Surface oxidation perturbs the thermal equilibrium concentration of point defects and analyses of the resulting effects on dopant diffusion showed that both V and I are present. Developments in experimental and theoretical works on Au diffusion in Si yielded a determination of the I-component and an estimate of the V-component of the Si self-diffusion coefficient. It is hoped that the I and V thermal equilibrium concentrations may be determined in the near future.A number of important physical aspects of the anomalous diffusion of P are now understood but a basically satisfactory model may need further work.

Thermal Equilibrium Concentrations and Effects of Ga Vacancies in n-TYPE GaAs

1993 ◽  
Vol 300 ◽  
Author(s):  
Teh Y. Tan ◽  
Homg-Ming You ◽  
Ulrich M. Gösele
Keyword(s):  
Temperature Dependence ◽  
Point Defect ◽  
Thermal Equilibrium ◽  
Quantitative Data ◽  
Equilibrium Concentration ◽  
Negative Temperature ◽  
Positive Temperature ◽  
Self Diffusion ◽  
N Doping ◽  
Equilibrium Concentrations

ABSTRACTWe have calculated the thermal equilibrium concentrations of the various Ga vacancy species in GaAs. That of the triply-negatively-charged Ga vacancy, V3Ga has been emphasized, since it dominates Ga self-diffusion and Ga-Al interdiffusion under intrinsic and ndoping conditions, as well as the diffusion of Si donor atoms occupying Ga sites. Under strong n-doping conditions, the thermal equilibrium V3Ga concentration, CeqvGa.3−(n), has been found to exhibit a temperature independence or a negative temperature dependence, in the sense that the CeqvGa.3−(n) value is either unchanged or increases as the temperature is lowered. This is contrary to the normal positive temperature dependence of point defect theerqmal equilibrium concentrations, which decreases as the temperature is lowered. This CeqvGa.3−(n) property provides explanations to a number of outstanding experimental results, either requiring the interpretation thatV3−Ga has attained its thermal equilibrium concentration at the onset of each experiment, or requiring mechanisms involving point defect non-equilibrium phenomena. Furthermore, there exist also a few quantitative data which are in agreement with the presently calculated results.

Determination of Diffusivities of Si Self-Diffusion and Si Self-Interstitials using Isotopically Enriched Single-or Multi-30Si Epitaxial Layers

2005 ◽  
Vol 864 ◽  
Author(s):  
S. Matsumoto ◽  
S.R. Aid ◽  
T. Sakaguchi ◽  
K. Toyonaga ◽  
Y. Nakabayashi ◽  
...  
Keyword(s):  
Thermal Equilibrium ◽  
Equilibrium Concentration ◽  
Sample Surface ◽  
Temperature Range ◽  
Self Diffusion ◽  
Si Substrates ◽  
Numerical Fitting ◽  
Si Isotopes ◽  
Secondary Ion

AbstractSelf-diffusivity of Si has been obtained over a wide temperature range (867°C-1300°C) using highly isotopically enriched 30Si epi-layers (99.88%) as a diffusion source into natural Si substrates. 30Si epi-layers were grown on both CZ-Si substrates and non-doped epi-layers grown on CZ-Si substrates using low pressure CVD with 30SiH4. Diffusion was performed in resistance-heated furnaces under a pure Ar atmosphere. After annealing, the concentrations of the respective Si isotopes were measured with secondary ion mass spectroscopy (SIMS). Diffusivity of 30Si (called Si self-diffusivity, DSD) was determined using a numerical fitting process with 30Si SIMS profiles. We found no major differences in self-diffusivity between bulk Si and epi-Si. Within the 867°C -1300°C range investigated, DSD can be described by an Arrhenius equation with one single activation enthalpy: DSD =14 exp (—4.37 eV/kT) cm2/s. The present result is in good agreement with that of Bracht et. al.Diffusivity and thermal equilibrium concentration of Si self-interstitials have been determined using multi-30Si epi-layers consisting of alternative layers with isotopically pure 30Si and natural Si. The sample surface was oxidized and the Si self-interstitials were introduced from the surface. Spreading of 30Si spikes of each layer due to the diffusion of Si self-interstitials generated at the surface was measured with SIMS analysis. The diffusivity of Si self-interstitials, DI, is obtained by fitting with experimental results. In the temperature range between 820 -920°C, DI and thermal equilibrium concentration of Si self-interstitials, CIi, are described by the Arrhenius equations DI3.48×104 exp (—3.82eV/KT) cm2/s and CIi= 9.62×1018 exp (—0.475eV/KT) cm-3, respectively.

The Nature of Point Defects and their Influence on Diffusion Processes in Silicon at High Temperatures

1982 ◽  
Vol 14 ◽  
Author(s):  
U. GÖsele ◽  
T.Y. Tan
Keyword(s):  
Diffusion Processes ◽  
Surface Oxidation ◽  
Group V ◽  
Group Iii ◽  
Self Diffusion ◽  
Slowing Down ◽  
Silicon Crystals ◽  
Order Of Magnitude ◽  
Theoretical Results

ABSTRACTThe paper highlights recent progress in understanding the role of vacancies and self-interstitials in self- and impurity diffusion in silicon above about 700°C. How surface oxidation of silicon leads to a perturbation of the pointdefect population is described. An analysis of the resulting oxidationenhanced or -retarded diffusion of group III and group V dopants shows that under thermal equilibrium as well as under oxidation conditions both vacancies and self-interstitials are present. For sufficiently long times vacancies and self-interstitials attain dynamical equilibrium which involves their recombination and spontaneous thermal creation in the bulk of silicon crystals. The existence and the nature of a recombination barrier slowing down the recombination process are discussed in this context. Recent experimental and theoretical results on the diffusion of gold in silicon enable us to determine the selfinterstitial component of silicon self-diffusion and to obtain an estimate of the respective vacancy contribution. The two components turn out to be of the same order of magnitude from 700°C up to the melting point.

Effect of cluster-gradient architecture of nanostructured topocomposites on features of tribointeraction with heterophased material

2020 ◽  
pp. 130-135
Author(s):  
D.N. Korotaev ◽  
K.N. Poleshchenko ◽  
E.N. Eremin ◽  
E.E. Tarasov
Keyword(s):  
Wear Resistance ◽  
Titanium Alloy ◽  
Energy Dissipation ◽  
Phase Structure ◽  
Diffusion Processes ◽  
Structural Phase ◽  
High Wear Resistance ◽  
Wear Characteristics ◽  
And Diffusion

The wear resistance and wear characteristics of cluster-gradient architecture (CGA) nanostructured topocomposites are studied. The specifics of tribocontact interaction under microcutting conditions is considered. The reasons for retention of high wear resistance of this class of nanostructured topocomposites are studied. The mechanisms of energy dissipation from the tribocontact zone, due to the nanogeometry and the structural-phase structure of CGA topocomposites are analyzed. The role of triboactivated deformation and diffusion processes in providing increased wear resistance of carbide-based topocomposites is shown. They are tested under the conditions of blade processing of heat-resistant titanium alloy.

Diffusion Mechanisms in Sige Alloys

1999 ◽  
Vol 568 ◽  
Author(s):  
Arthur F.W. Willoughby ◽  
Janet M. Bonar ◽  
Andrew D.N. Paine
Keyword(s):  
Diffusion Processes ◽  
Dopant Diffusion ◽  
Elemental Silicon ◽  
Self Diffusion ◽  
Si Substrates ◽  
Marker Layer ◽  
Diffusion Mechanisms ◽  
Silicon And Germanium ◽  
Charged Defects

ABSTRACTInterest in diffusion processes in SiGe alloys arises from their potential in HBT's, HFET's, and optoelectronics devices, where migration over distances as small as a few nanometres can be significant. Successful modelling of these processes requires a much improved understanding of the mechanisms of self- and dopant diffusion in the alloy, although recent progress has been made. It is the purpose of this review to set this in the context of diffusion processes in elemental silicon and germanium, and to identify how this can help to elucidate behaviour in the alloy. Firstly, self diffusion processes are reviewed, from general agreement that self-diffusion in germanium is dominated by neutral and acceptor vacancies, to the position in silicon which is still uncertain. Germanium diffusion in silicon, however, appears to be via both vacancy and interstitial processes, and in the bulk alloy there is evidence for a change in dominant mechanism at around 35 percent germanium. Next, a review of dopant diffusion begins with Sb, which appears to diffuse in germanium by a mechanism similar to self-diffusion, and in silicon via monovacancies also, from marker layer evidence. In SiGe, the effects of composition and strain in epitaxial layers on Si substrates are also consistent with diffusion via vacancies, but questions still remain on the role of charged defects. The use of Sb to monitor vacancy effects such as grown-in defects by low temperature MBE, are discussed. Lastly, progress in assessing the role of vacancies and interstitials in the diffusion of boron is reviewed, which is dominated by interstitials in silicon-rich alloys, but appears to change to domination by vacancies at around 40 percent germanium, although studies in pure germanium are greatly needed.

Self Diffusion in SiC: the Role of Intrinsic Point Defects

2001 ◽  
Vol 353-356 ◽  
pp. 323-326 ◽  
Author(s):  
Alexander Mattausch ◽  
M. Bockstedte ◽  
Oleg Pankratov
Keyword(s):  
Point Defects ◽  
Intrinsic Point Defects ◽  
Self Diffusion

scholarly journals In situ X-ray tomography densification of firn: The role of mechanics and diffusion processes

2019 ◽  
Vol 167 ◽  
pp. 210-220 ◽  
Author(s):  
Alexis Burr ◽  
Pierre Lhuissier ◽  
Christophe L. Martin ◽  
Armelle Philip
Keyword(s):  
Diffusion Processes ◽  
X Ray ◽  
And Diffusion

Atomistic Simulations of Point Defect Properties in Silicon

1992 ◽  
Vol 278 ◽  
Author(s):  
Dimitrios Maroudas ◽  
Robert A. Brown
Keyword(s):  
Distribution Function ◽  
Point Defects ◽  
Thermal Equilibrium ◽  
Harmonic Approximation ◽  
Reference State ◽  
Atomistic Simulations ◽  
Free Energies ◽  
Systematic Analysis ◽  
Equilibrium Concentrations ◽  
Cumulant Analysis

AbstractA systematic analysis based on atomistic simulations is presented for the calculation of energies and equilibrium concentrations of intrinsic point defects in silicon. Calculation of Gibbs free energies is based on the quasi-harmonic approximation for the reference state and the cumulant analysis of the enthalpy distribution function from Monte Carlo simulations in the reference state. Results are presented for the temperature dependence of enthalpies, volumes, and free energies of formation and thermal equilibrium concentrations of vacancies and self-interstitials.

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