Computer Simulation of Annealing after Cluster Ion Implantation

1998 ◽  
Vol 532 ◽  
Author(s):  
Z. Insepov ◽  
T. Aoki ◽  
J. Matsuo ◽  
I. Yamada
Keyword(s):  
Activation Energy ◽  
Molecular Dynamics ◽  
Computer Simulation ◽  
Ion Implantation ◽  
Temperature Region ◽  
Diffusion Coefficients ◽  
Metropolis Monte Carlo ◽  
Cluster Ion ◽  
Higher Temperature ◽  
Substrate Temperatures

ABSTRACTMolecular Dynamics (MD) and Metropolis Monte-Carlo (MMC) models of monomer B and decaborane implantation into Si and following rapid thermal annealing (RTA) processes have been developed in this paper. The implanted B dopant diffusion coefficients were obtained for different substrate temperatures. The simulation of decaborane ion implantation has revealed the formation of an amorphized area in a subsurface region, much larger than that of a single B+ implantation, with the same energy per ion. The B diffusion coefficient shows an unusual temperature dependence with two different activation energies. Low activation energy, less than 0.2, was obtained for a low-temperature region, and a higher activation energy, ˜ 3 ev, for a higher-temperature region which is typical for the RTA processing. The higher activation energy is comparable with the equilibrium activation energy, 3.4 ev, for B diffusion in Si.

Computer Simulation of Decaborane Implantation into Silicon, Annealing and Re-crystallization of Silicon

2001 ◽  
Vol 669 ◽  
Author(s):  
Zinetulla Insepov ◽  
Isao Yamada
Keyword(s):  
Molecular Dynamics ◽  
Computer Simulation ◽  
Ion Implantation ◽  
Energy Range ◽  
Linear Dependence ◽  
Md Simulation ◽  
Relaxation Technique ◽  
Si Substrate ◽  
Implantation Process ◽  
Impact Energies

ABSTRACTMolecular Dynamics (MD) and Activation-Relaxation Technique (ART) models of decaborane ion implantation into Si and following rapid thermal annealing (RTA) processes have been developed. The B and Si atomic positions for implantation of accelerated decaborane ions, with total energy 3.5- 15 KeV, into Si substrate were obtained by MD simulation. The main difference between monomer and decaborane ion implantation with the same doses is the formation of a large amorphized area in a subsurface region for the decaborane case. The number of displaced Si atoms shows non-linear energy dependence at low impact energies. At higher energies ofthe investigated range of the decaborane energy range, however, a linear dependence is observed in accordancewith the prediction of the Kinchin-Pease formula. A new method that incorporates Activation-Relaxation Technique (ART) with MD has been developed and used to study re-crystallization of Si amorphized in the implantation process.

Steady State Conduction Behaviour of Liquid Crystalline Polyurethane

2013 ◽  
Vol 856 ◽  
pp. 210-214
Author(s):  
Jitender Kumar Quamara ◽  
Satish Kumar Mahna ◽  
Sohan Lal ◽  
Pushkar Raj
Keyword(s):  
Activation Energy ◽  
Steady State ◽  
Temperature Region ◽  
Liquid Crystalline ◽  
Ionic Conduction ◽  
Schottky Type ◽  
Order Of Magnitude ◽  
Higher Temperature ◽  
Lower Temperature ◽  
Type Conduction

The steady state measurements in Liquid crystalline polyurethane (LCPU) have been investigated for different fields (4 - 45 kV/cm) and temperatures (50°-220°C). The nature of conduction processes has been determined by estimating ion jump distances (a) and Schottky coefficients. The order of magnitude of a in the temperature region 150°C and below does not seem to support an ionic conduction. However the magnitude of a at higher temperatures (180°C and above) indicates the possibility of ionic conduction. There is a definite possibility of a Schottky type conduction at lower temperature and a Poole Frankel type conduction at higher temperature (100°C). The activation energy associated with the high temperature region lies between 0.26 eV and 0.65 eV depending on the field whereas in the low temperature region the activation energy lies between 0.82 eV and 0.95 eV depending on the applied electric field. The dual slopes in the log I versus 1/T curves indicate the presence of more than one type of trapping levels.

scholarly journals Цепочки карбинофуллеренов C-=SUB=-20-=/SUB=-

2019 ◽  
Vol 61 (4) ◽  
pp. 793
Author(s):  
А.И. Подливаев ◽  
Л.А. Опенов
Keyword(s):  
Activation Energy ◽  
Molecular Dynamics ◽  
Thermal Stability ◽  
Computer Simulation ◽  
Binding Energies ◽  
Decay Process ◽  
Arrhenius Law ◽  
Carbon Structure ◽  
One Dimensional ◽  
Method Of Molecular Dynamics

AbstractThe results of computer simulation of a new one-dimensional carbon structure representing chains composed of C_20 carbinofullerenes are presented. Their binding energies are determined. Their thermal stability is studied by the method of molecular dynamics. The resistance of chains to stretching is also studied. It is shown that breaking the bond between adjacent carbinofullerene moieties in the chain is a preferred channel for thermal and deformational destruction. The ultimate strains of chains and also the temperature dependence of their lifetime until the time of decay are determined. Using different approaches, the activation energy values and the frequency factors of the decay process in the Arrhenius law are found.

Cluster ion implantation: a molecular dynamics study

2000 ◽  
Vol 3 (1-2) ◽  
pp. 91-95 ◽  
Author(s):  
Sigeo Ihara ◽  
Satoshi Itoh ◽  
James C Greer
Keyword(s):  
Molecular Dynamics ◽  
Ion Implantation ◽  
Cluster Ion

scholarly journals Molecular Dynamics Simulations of Vacancy Generation and Migration near a Monocrystalline Silicon Surface during Energetic Cluster Ion Implantation

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 146
Author(s):  
Guoying Liang ◽  
Haowen Zhong ◽  
Yinong Wang ◽  
Shijian Zhang ◽  
Mofei Xu ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Ion Implantation ◽  
Molecular Dynamics Simulations ◽  
Silicon Surface ◽  
Amorphous Structure ◽  
Monocrystalline Silicon ◽  
Vacancy Generation ◽  
Cluster Ion ◽  
And Migration ◽  
Dynamics Simulations

The process of ion implantation often involves vacancy generation and migration. The vacancy generation and migration near a monocrystalline silicon surface during three kinds of energetic Si35 cluster ion implantations were investigated by molecular dynamics simulations in the present work. The patterns of vacancy generation and migration, as well as the implantation-induced amorphous structure, were analyzed according to radial distribution function, Wigner–Seitz cell, and identify diamond structure analytical methods. A lot of vacancies rapidly generate and migrate in primary directions and form an amorphous structure in the first two picoseconds. The cluster with higher incident kinetic energy can induce the generation and migration of more vacancies and a deeper amorphous structure. Moreover, boundaries have a loading–unloading effect, where interstitial atoms load into the boundary, which then acts as a source, emitting interstitial atoms to the target and inducing the generation of vacancies again. These results provide more insight into doping silicon via ion implantation.

Interlayer mixing in GaAs/AlxGa1-xAs heterostructures as a result of Se+ ion implantation

1988 ◽  
Vol 46 ◽  
pp. 908-909
Author(s):  
E.G. Bithell ◽  
W.M. Stobbs
Keyword(s):  
Ion Implantation ◽  
Diffusion Coefficients ◽  
Dark Field ◽  
Atomic Mass ◽  
Composition Profile ◽  
Semiconductor Heterostructures ◽  
Transmission Electron ◽  
Microscope Images ◽  
Damage Process ◽  
Electron Energy Loss

It is well known that the microstructural consequences of the ion implantation of semiconductor heterostructures can be severe: amorphisation of the damaged region is possible, and layer intermixing can result both from the original damage process and from the enhancement of the diffusion coefficients for the constituents of the original composition profile. A very large number of variables are involved (the atomic mass of the target, the mass and energy of the implant species, the flux and the total dose, the substrate temperature etc.) so that experimental data are needed despite the existence of relatively well developed models for the implantation process. A major difficulty is that conventional techniques (e.g. electron energy loss spectroscopy) have inadequate resolution for the quantification of any changes in the composition profile of fine scale multilayers. However we have demonstrated that the measurement of 002 dark field intensities in transmission electron microscope images of GaAs / AlxGa1_xAs heterostructures can allow the measurement of the local Al / Ga ratio.

scholarly journals Unveiling Carbon Dioxide and Ethanol Diffusion in Carbonated Water-Ethanol Mixtures by Molecular Dynamics Simulations

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1711
Author(s):  
Mohamed Ahmed Khaireh ◽  
Marie Angot ◽  
Clara Cilindre ◽  
Gérard Liger-Belair ◽  
David A. Bonhommeau
Keyword(s):  
Carbon Dioxide ◽  
Molecular Dynamics ◽  
Diffusion Coefficients ◽  
Hydrodynamic Radius ◽  
Md Simulations ◽  
Molecular Models ◽  
Experimental Values ◽  
Carbon Dioxide Co2 ◽  
Dynamics Simulations ◽  
Apparent Disagreement

The diffusion of carbon dioxide (CO2) and ethanol (EtOH) is a fundamental transport process behind the formation and growth of CO2 bubbles in sparkling beverages and the release of organoleptic compounds at the liquid free surface. In the present study, CO2 and EtOH diffusion coefficients are computed from molecular dynamics (MD) simulations and compared with experimental values derived from the Stokes-Einstein (SE) relation on the basis of viscometry experiments and hydrodynamic radii deduced from former nuclear magnetic resonance (NMR) measurements. These diffusion coefficients steadily increase with temperature and decrease as the concentration of ethanol rises. The agreement between theory and experiment is suitable for CO2. Theoretical EtOH diffusion coefficients tend to overestimate slightly experimental values, although the agreement can be improved by changing the hydrodynamic radius used to evaluate experimental diffusion coefficients. This apparent disagreement should not rely on limitations of the MD simulations nor on the approximations made to evaluate theoretical diffusion coefficients. Improvement of the molecular models, as well as additional NMR measurements on sparkling beverages at several temperatures and ethanol concentrations, would help solve this issue.

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