Ctivation Energies Of Interstitial Oxygen Diffusion In Silicon Containing Hydrogen

1996 ◽  
Vol 442 ◽  
Author(s):  
W. Wijaranakula
Keyword(s):  
Oxygen Diffusion ◽  
Thermal Equilibrium ◽  
Equilibrium Concentration ◽  
Activation Energies ◽  
Time Dependent ◽  
Rate Theory ◽  
Interstitial Oxygen ◽  
Hydrogen Saturation ◽  
Thermal Donor ◽  
Numerical Fitting

AbstractThe activation energies of interstitial oxygen diffusion in silicon containing hydrogen were derived from the results obtained from thermal donor generation experiments using numerical fitting based upon the classical nucleation rate theory and the time-dependent reduction of interstitial oxygen concentration resulting from oxygen aggregation. By using a new thermal equilibrium concentration of hydrogen at a pressure of 1 atm of 2×1021 exp(- 1.75 eV/kT), and the expression for the dependence of hydrogen thermal equilibrium concentration on the partial pressure P given as P0.65 times the hydrogen thermal equilibrium concentration at a pressure of 1 atm, the correlation between the activation energies of interstitial oxygen diffusion and hydrogen saturation is observed to be linearlogarithmic. In the hydrogen saturation range between 103 and 106, the activation energies of interstitial oxygen diffusion are estimated to be between 0.03 and 0.21 eV lower than the normal value of 2.53 eV. This implies that enhanced oxygen diffusion may occur primarily under hydrogen saturation conditions.

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.

On the Question of Oxygen Diffusion During Oxygen Related Thermal Donor Formation In Silicon.

1986 ◽  
Vol 71 ◽  
Author(s):  
G. S. Oehrlein ◽  
T. Y. Tan ◽  
R. L. Kleinhenz ◽  
J. L. Lindstrom
Keyword(s):  
Heat Treatment ◽  
Activation Energy ◽  
Oxygen Content ◽  
Oxygen Diffusion ◽  
Heat Treatments ◽  
The Other ◽  
Interstitial Oxygen ◽  
Thermal Donor ◽  
Oxygen Diffusivity ◽  
Donor Formation

In an attempt to decide the question whether enhanced oxygen diffusion is important for heat-treatments of silicon at ∼450ºC where thermal donors are formed we have conducted two types of experiments aimed at providing a measure of the “effective” oxygen diffusivity. First, we have extensively measured the temperature dependence of the thermal donor introduction rate for very short heat treatment times (20min). This measurement provides the thermal activation energy of TD formation. Since effects of long range diffusion and formation of large oxygen clusters are negligible for suchtimes and temperatures and, presumably, thermal donor formation at the lowest heat treatment temperatures is oxygen diffusion limited, it should be possible to interprete the obtained activation energy in terms of oxygen diffusivity. The change of the interstitialoxygen content is immeasureable for 20min heat treatment times. Therefore, the decay of the interstitial oxygen content was measured for longer heat treatments at 450ºC (up to 500hours). The two experiments are complementary in several ways: In one experiment the oxygen diffusion activation energy is extracted, while the other measurement provides the value of the diffusion coefficient at a given temperature. In one case thermal donors are monitored for short heat treatment times while in the other experiment the interstitial oxygen content is measured for long heat treatment times. The present measurements are different from other diffusion experiments in this temperature range where theatomic jump of isolated oxygen is monitored [1]. Here we attempt to extract an effective oxygen diffusivity under conditions of thermal donor formation since the thermal donor formation process itself might be the cause of an enhanced oxygen diffusivity.

Oxygen diffusion process in a Ba0.96La0.04SnO3thin film on SrTiO3(001) substrate as investigated by time-dependent Hall effect measurements

2015 ◽  
Vol 212 (7) ◽  
pp. 1487-1493 ◽  
Author(s):  
Woong-Jhae Lee ◽  
Hyung Joon Kim ◽  
Egon Sohn ◽  
Hoon Min Kim ◽  
Tai Hoon Kim ◽  
...  
Keyword(s):  
Diffusion Process ◽  
Hall Effect ◽  
Oxygen Diffusion ◽  
Time Dependent ◽  
Hall Effect Measurements

Kinetic Model of Thermal Donor Evolution

1997 ◽  
Vol 469 ◽  
Author(s):  
K. F. Kelton ◽  
R. Falster
Keyword(s):  
Interstitial Oxygen ◽  
Oxygen Loss ◽  
Free Oxygen ◽  
Czochralski Silicon ◽  
Thermal Donor ◽  
Cluster Evolution ◽  
Oxygen Precipitation ◽  
High Diffusion Rate ◽  
Normal Diffusion ◽  
Small Clusters

ABSTRACTKinetic aspects of thermal donor (TD) formation in Czochralski silicon are shown to be consistent with the evolution of small oxygen clusters, as described within the classical theory of nucleation. Predictions for TD generation and interstitial oxygen loss are presented. Favorable agreement with experimental data requires that the rate constants describing cluster evolution be increased over those expected for a oliffusion-limited flux based on a normal diffusion coefficient for oxygen in silicon. This may signal an anomalously high diffusion rate for temperatures less than 500°C, as has been suggested by others. However, it may instead signal an enhanced concentration of free oxygen near clusters smaller than the critical size for nucleation. This is expected when the interfacial attachment rates become comparable with the rates at which oxygen atoms arrive in the vicinity of the sub-critical clusters. The link between thermal donor generation and oxygen precipitation processes demonstrated here provides a consistent framework for better understanding and controlling oxygen precipitation in silicon. Further, the kinetic TD generation and oxygen loss data provide a new window into the dynamical processes for small clusters, which underlie all nucleation phenomena.

The application of rate theory to time-dependent deformation of concrete

1974 ◽  
Vol 26 (89) ◽  
pp. 191-197 ◽  
Author(s):  
F. H. Wittmann ◽  
J. Lukas
Keyword(s):  
Time Dependent ◽  
Rate Theory

scholarly journals Kinetic Monte Carlo Simulation of Oxygen Diffusion in Ytterbium Disilicate

MRS Advances ◽  
2016 ◽  
Vol 1 (17) ◽  
pp. 1203-1208 ◽  
Author(s):  
Brian S. Good
Keyword(s):  
Monte Carlo ◽  
High Temperature ◽  
Oxygen Diffusion ◽  
Density Functional ◽  
Defect Formation ◽  
Kinetic Monte Carlo ◽  
Interstitial Oxygen ◽  
Temperature Oxidation ◽  
Electron Volt ◽  
Formation Energies

ABSTRACTYtterbium disilicate is of interest as a potential environmental barrier coating for aerospace applications, notably for use in next generation jet turbine engines. In such applications, the transport of oxygen and water vapor through these coatings to the ceramic substrate is undesirable if high temperature oxidation is to be avoided. In an effort to understand the diffusion process in these materials, we have performed kinetic Monte Carlo simulations of vacancy-mediated and interstitial oxygen diffusion in Ytterbium disilicate. Oxygen vacancy and interstitial site energies, vacancy and interstitial formation energies, and migration barrier energies were computed using Density Functional Theory. We have found that, in the case of vacancy-mediated diffusion, many potential diffusion paths involve large barrier energies, but some paths have barrier energies smaller than one electron volt. However, computed vacancy formation energies suggest that the intrinsic vacancy concentration is small. In the case of interstitial diffusion, migration barrier energies are typically around one electron volt, but the interstitial defect formation energies are positive, with the result that the disilicate is unlikely to exhibit experience significant oxygen permeability except at very high temperature.

Study of Oxygen Diffusion in Polycrystalline ZnO by SIMS

2009 ◽  
Vol 289-292 ◽  
pp. 523-530
Author(s):  
Antônio Claret Soares Sabioni ◽  
Antônio Márcio J.M. Daniel ◽  
Anne Marie Huntz ◽  
Wilmar Barbosa Ferraz ◽  
François Jomard
Keyword(s):  
Grain Boundary ◽  
Oxygen Pressure ◽  
Diffusion Coefficients ◽  
Effective Charge ◽  
Oxygen Diffusion ◽  
Secondary Ion Mass Spectrometry ◽  
Diffusion Mechanism ◽  
Bulk Diffusion ◽  
Interstitial Oxygen ◽  
Exchange Method

Oxygen diffusion coefficients were measured in polycrystalline ZnO by means of the gas-solid exchange method using the isotope 18O as the oxygen tracer. The diffusion annealings were performed at 892oC and 992oC, in an Ar+18O2 atmosphere under oxygen partial pressures from 0.1 to 1atm. After the diffusion annealings, the 18O diffusion profiles were established by secondary ion mass spectrometry (SIMS). Increasing the oxygen pressure leads to an increase of the oxygen diffusion in ZnO. The bulk diffusion coefficients depends on oxygen pressure according to , at 882oC, or , at 992oC, which indicates that the oxygen bulk diffusion mechanism should preferentially take place by means of interstitial oxygen having a null effective charge. The grain boundary diffusion coefficients show little dependence on oxygen pressure at 882oC, given by , which should correspond to a diffusion mechanism by means of interstitial oxygen, with a double negative charge, but at 992oC this dependence is corresponding to a diffusion mechanism by interstitial oxygen having a null effective charge. The results also show that the grain boundary is a fast path for the oxygen diffusion in polycrystalline ZnO.

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