Possible Mechanism Of The Stress Evolution And Point Defects Generation During The Solid Phase Epitaxial Silicide Growth.

1991 ◽  
Vol 238 ◽  
Author(s):  
A. G. Italjantsev ◽  
A.Yu. Kuznetsov
Keyword(s):  
Point Defect ◽  
Point Defects ◽  
Solid Phase ◽  
Vacancy Concentration ◽  
Local Stress ◽  
Thin Metal Film ◽  
Generation Rate ◽  
Solid State Reactions ◽  
Thermodynamic Force ◽  
Defect Generation

ABSTRACTIn this paper we present a model of nonequilibrium point defect generation in the silicon substrate during solid state reactions of the surface suicides formation, resulting from the interaction between the substrate and the thin metal film. The model is based on the following principles. The local stress, which is appearing during each act of the suicide molecule (MexSiy) creation at the suicide - silicon interface, relaxes by the generation of ηv point defects. The point defect generation rate (m is the suicide growth rate) has been defined by the mininimization of the system free energy AG, which includes the enthalpy of chemical reaction ΔG the value of the relaxed elastic energyμ is the silicon shear modulus, Ω = (xΩMe+yΩSi) is the combined volume of metal and silicon atoms with stoichiometric coefficients, ΔΩ = (ΩMexSiy - Ω), ΩV is the vacancy volume in the matrix; and the term ΔGd = ηVkTln(C/C0) which takes into account the energy of the solid solution of noninteracting point defects, where C° is an equilibrium vacancy concentration and C is the real vacancy concentration. The estimations show that there is not any essential thermodynamic force which may prevent stress relaxation for any reasonable point defect supersaturation. For this case point defect generation rate may be written as jV = m(ΔΩ/ΩV). For the reactions of the initial phase formation in the Me-Si structures the values of ΔG*el, ηV and jV have been calculated and it has been shown that vacancy concentration can reach the values of 1015 - 1016 cm-3 at the regions nearest to the interface even during initial low temperature stages of the Ni, Pt, Cr suicide formation with the metal atoms are predominant moving species.

scholarly journals Role of Interface in Multilayered Composites under Irradiation: A Mathematical Investigation

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Jaime Ortún-Palacios ◽  
Antonio Mario Locci ◽  
Sarah Fadda ◽  
Francesco Delogu ◽  
Santiago Cuesta-López
Keyword(s):  
Point Defect ◽  
Point Defects ◽  
Diffusion Rate ◽  
Temporal Evolution ◽  
Vacancy Concentration ◽  
Balance Equations ◽  
Layer System ◽  
Mathematical Investigation ◽  
Multilayered Composites

A continuum model of point-defects evolution during irradiation of a multilayer composite material is presented in this work. Nonstationary balance equations are used to describe production, recombination, transport, and annihilation, or removal, of vacancies and interstitials in a β-α-β three-layer system (α = Cu and β = Nb, V, or Ni). In addition, transport and trapping of point-defects at interfaces are taken into account. Numerical investigation on similarities and differences between Cu/Nb, Cu/V, and Cu/Ni systems is also performed. A general comparison of model results reveals that average vacancy concentration is typically higher than SIA one in both layers for all the systems investigated. This is a consequence of the higher diffusion rate of SIAs with respect to vacancies. Stationary state is reached without saturating interface point-defect traps by all systems but Cu/Ni for the case of SIAs. It can be also seen that Cu/Nb and Cu/V systems have a very similar behavior regarding point-defect temporal evolution in copper (layer α), while higher SIA concentration at steady state is shown therein by the Cu/Ni structure. Moreover, Cu/V system displays the lower stationary vacancy concentration in layer β.

scholarly journals Co-regulation of the copper vacancy concentration and point defects leading to the enhanced thermoelectric performance of Cu3In5Te9-based chalcogenides

RSC Advances ◽  
2019 ◽  
Vol 9 (54) ◽  
pp. 31747-31752 ◽  
Author(s):  
Min Li ◽  
Yong Luo ◽  
Xiaojuan Hu ◽  
Zhongkang Han ◽  
Xianglian Liu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Point Defect ◽  
Carrier Concentration ◽  
Point Defects ◽  
Lattice Thermal Conductivity ◽  
Vacancy Concentration ◽  
Thermoelectric Performance ◽  
High Carrier Concentration ◽  
High Carrier

Co-regulation of both the copper vacancy concentration (Vc) and point defect GaIn realizing the high carrier concentration and low lattice thermal conductivity in Cu3In5Te9-based chalcogenides simultaneously.

Detection of a point defect in a silicon single crystal by high-resolution TEM

1995 ◽  
Vol 53 ◽  
pp. 466-467
Author(s):  
M. Awaji
Keyword(s):  
High Resolution ◽  
Single Crystal ◽  
Point Defect ◽  
Point Defects ◽  
Noise Level ◽  
Dark Field ◽  
Silicon Single Crystal ◽  
High Resolution Image ◽  
Dark Field Imaging ◽  
Field Imaging

It is necessary to improve the resolution, brightness and signal-to-noise ratio(s/n) for the detection and identification of point defects in crystals. In order to observe point defects, multi-beam dark-field imaging is one of the useful methods. Though this method can improve resolution and brightness compared with dark-field imaging by diffuse scattering, the problem of s/n still exists. In order to improve the exposure time due to the low intensity of the dark-field image and the low resolution, we discuss in this paper the bright-field high-resolution image and the corresponding subtracted image with reference to a changing noise level, and examine the possibility for in-situ observation, identification and detection of the movement of a point defect produced in the early stage of damage process by high energy electron bombardment.The high-resolution image contrast of a silicon single crystal in the [10] orientation containing a triple divacancy cluster is calculated using the Cowley-Moodie dynamical theory and for a changing gaussian noise level. This divacancy model was deduced from experimental results obtained by electron spin resonance. The calculation condition was for the lMeV Berkeley ARM operated at 800KeV.

Point defect trapping in solid‐phase epitaxially grown silicon‐antimony alloys

1984 ◽  
Vol 55 (4) ◽  
pp. 837-840 ◽  
Author(s):  
S. J. Pennycook ◽  
J. Narayan ◽  
O. W. Holland
Keyword(s):  
Point Defect ◽  
Solid Phase ◽  
Antimony Alloys

scholarly journals Reactivity of fluorographene is triggered by point defects: beyond the perfect 2D world

Nanoscale ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 4696-4707 ◽  
Author(s):  
Miroslav Medveď ◽  
Giorgio Zoppellaro ◽  
Juri Ugolotti ◽  
Dagmar Matochová ◽  
Petr Lazar ◽  
...  
Keyword(s):  
Point Defect ◽  
Point Defects

Understanding the links between nucleophilic/reductive strength of the environment, formation of radicals and point defect characteristics is crucial for achieving control over the functionalization of fluorographene.

Displacement cascade evolution in tungsten with pre-existing helium and hydrogen clusters: a molecular dynamics study

2020 ◽  
Vol 111 (8) ◽  
pp. 698-705
Author(s):  
Mohammad Abu-Shams ◽  
Jeffery Moran ◽  
Ishraq Shabib
Keyword(s):  
Molecular Dynamics ◽  
Point Defect ◽  
Radiation Damage ◽  
Point Defects ◽  
High Energy ◽  
Dynamics Simulation ◽  
Power Relationship ◽  
Hydrogen Clusters ◽  
Displacement Cascades ◽  
Hydrogen Defects

Abstract The effects of radiation damage on bcc tungsten with preexisting helium and hydrogen clusters have been investigated in a high-energy environment via a comprehensive molecular dynamics simulation study. This research determines the interactions of displacement cascades with helium and hydrogen clusters integrated into a tungsten crystal generating point defect statistics. Helium or hydrogen clusters of atoms~0.1% of the total number of atoms have been randomly distributed within the simulation model and primary knock-on-atom (PKA) energies of 2.5, 5, 7.5 and 10 keV have been used to generate displacement cascades. The simulations quantify the extent of radiation damage during a simulated irradiation cycle using the Wigner-Seitz point defect identification technique. The generated point defects in crystals with and without pre-existing helium/hydrogen defects exhibit a power relationship with applied PKA energy. The point defects are classified by their atom type, defect type, and distribution within the irradiated model. The presence of pre-existing helium and hydrogen clusters significantly increases the defects (5 - 15 times versus pure tungsten models). The vacancy composition is primarily tungsten (e. g., ~70% at 2.5 keV) in models with pre-existing helium, but the interstitials are primarily He (e. g., ~89% at 10 keV). On the other hand, models with pre-existing hydrogen have a vacancy composition that is primarily tungsten (more than 90% irrespective of PKA energy), and the interstitial composition is more balanced between tungsten (average 46%) and hydrogen (average 54%) interstitials across the PKA range. The distribution of the atoms reveals that the tungsten point defects prefer to reside close to the position of cascade initiation, but helium or hydrogen defects reside close to the positions where clusters are built.

scholarly journals Silver vacancy concentration engineering leading to the ultralow lattice thermal conductivity and improved thermoelectric performance of Ag1-xInTe2

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yaqiong Zhong ◽  
Yong Luo ◽  
Xie Li ◽  
Jiaolin Cui
Keyword(s):  
Crystal Structure ◽  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Point Defects ◽  
Lattice Thermal Conductivity ◽  
Vacancy Concentration ◽  
Antisite Defect ◽  
Thermoelectric Performance ◽  
Callaway Model

AbstractAgInTe2 compound has not received enough recognition in thermoelectrics, possibly due to the fact that the presence of Te vacancy (VTe) and antisite defect of In at Ag site (InAg) degrades its electrical conductivity. In this work, we prepared the Ag1-xInTe2 compounds with substoichiometric amounts of Ag and observed an ultralow lattice thermal conductivity (κL = 0.1 Wm−1K−1) for the sample at x = 0.15 and 814 K. This leads to more than 2-fold enhancement in the ZT value (ZT = 0.62) compared to the pristine AgInTe2. In addition, we have traced the origin of the untralow κL using the Callaway model. The results attained in this work suggest that the engineering of the silver vacancy (VAg) concentration is still an effective way to manipulate the thermoelectric performance of AgInTe2, realized by the increased point defects and modified crystal structure distortion as the VAg concentration increases.

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