The Study of Si, Se and O-Implanted GaAs by Slow Positrons

1992 ◽  
Vol 262 ◽  
Author(s):  
S. Fujii ◽  
S. Shikata ◽  
L. Wei ◽  
S. Tanigaw
Keyword(s):  
Positron Beam ◽  
Annealed Specimen ◽  
Electrical Characteristics ◽  
High Concentration ◽  
Positron Energy ◽  
Vacancy Clusters ◽  
Activation Efficiency ◽  
Before And After ◽  
Parallel Measurement ◽  
Variable Energy

ABSTRACTVariable-energy (0–30keV) positron beam studies have been carried out on 200 keV Se-implanted and 70 keV Si-implanted GaAs specimens before and after annealing for electrical activation. From the measurements of Doppler broadened profiles as a function of incident positron energy, it was found that vacancy clusters with high concentration were introduced in the annealed specimen after Se implantation. From the parallel measurement of electrical characteristics, a higher activation efficiency was found for the higher concentration of vacancy clusters. That fact implies that electrons supplied by the activation of Se also convert the charge state of As vacancies from positive to negative. In contrast, no vacancy clusters were introduced in the Si-implanted GaAs. On the other hand, oxygen clustering was found in annealed specimen after O implantation.

Growth of Vacancy Clusters During Post-Irradiation Annealing of Ion Implanted Silicon,

1995 ◽  
Vol 396 ◽  
Author(s):  
A. van Veen ◽  
H. Schut ◽  
A. Rivera ◽  
A.V. Fedorov
Keyword(s):  
Cavity Growth ◽  
Positron Beam ◽  
Vacancy Cluster ◽  
High Dose ◽  
High Concentration ◽  
Vacancy Clusters ◽  
Dissociation Energies ◽  
Beam Analysis ◽  
Growth Barriers ◽  
Silicon Based

AbstractAnnealing experiments of deuterium implanted silicon have been performed while positron beam analysis was used for monitoring the cavity growth. The experiments indicate up to annealing temperature 500° C similar defect evolution for both the low dose of 1016 cm-2 as for a 3 times higher dose. At this temperature the deuterium stabilized vacancy clusters dissociate and only in the case of the high dose micro-cavities are formed. Monte Carlo simulations of vacancy cluster growth in silicon based on vacancy cluster dissociation energies, calculated with the Stillinger Weber potential, have been performed. The results indicate that for low initial defect concentrations vacancy clusters might be hindered to grow because the vacancy binding energy of the clusters does not increase monotonically with the cluster size. Only a high concentration guarantees that growth barriers will be overcome.

scholarly journals Slow positron beam at the JINR, Dubna

Nukleonika ◽  
2015 ◽  
Vol 60 (4) ◽  
pp. 725-728 ◽  
Author(s):  
Paweł Horodek ◽  
Andrey G. Kobets ◽  
Igor N. Meshkov ◽  
Alexey A. Sidorin ◽  
Oleg S. Orlov
Keyword(s):  
Diffusion Length ◽  
Nuclear Research ◽  
Positron Beam ◽  
Positron Annihilation Spectroscopy ◽  
Low Energy ◽  
Positron Energy ◽  
Slow Positron ◽  
Tungsten Foil ◽  
Sample Chamber ◽  
Variable Energy

Abstract The Low Energy Positron Toroidal Accumulator (LEPTA) at the Joint Institute for Nuclear Research (JINR) proposed for generation of positronium in flight has been adopted for positron annihilation spectroscopy (PAS). The positron injector generates continuous slow positron beam with positron energy range between 50 eV and 35 keV. The radioactive 22Na isotope is used. In distinction to popular tungsten foil, here the solid neon is used as moderator. It allows to obtain the beam intensity of about 105 e+/s width energy spectrum characterized by full width at half maximum (FWHM) of 3.4 eV and a tail to lower energies of about 30 eV. The paper covers the characteristic of variable energy positron beam at the LEPTA facility: parameters, the rule of moderation, scheme of injector, and transportation of positrons into the sample chamber. Recent status of the project and its development in the field of PAS is discussed. As an example, the measurement of the positron diffusion length in pure iron is demonstrated.

B+, P+, AS+ and Si+ Ion Implantation Induced Defects in Silicon Studied by a Variable-Energy Positron Beam

1992 ◽  
Vol 262 ◽  
Author(s):  
Jun Sugiura ◽  
Makoto Ogasavara ◽  
Akira Uedono ◽  
Long Vei ◽  
Shoichiro Tanigava
Keyword(s):  
Ion Beam ◽  
Positron Beam ◽  
Beam Current ◽  
Positron Energy ◽  
Beam Depth ◽  
Induced Defects ◽  
Higher Doses ◽  
Annealing Experiments ◽  
Vacancy Type Defect ◽  
Variable Energy

ABSTRACTVacancy type defects introduced by As+, P+, Si+ and B+ ion implantations into Si (100) single crystals were studied by a variable-energy positron beam. Depth distributions of the defects were obtained from measurements of Doppler broadening profiles of the positron annihilation as a function of incident positron energy. The results showed that this technique is sensitive not only to a vacancy type defect but to formation of amorphous regions. The defects introduced by lower doses were identified as vacancy clusters from isochronal annealing experiments. By higher doses such as 5×1014 /cm2, amorphous layers were formed for 150KeV As+, 150KeV P+, and 200KeV Si+ ions, and it was not formed for 80KeV B+ by the dose of 5×1015 /cm2. These results are consistent with the calculated critical doses. In the case of B+, pre-amorphous formation was observed with higher ion beam current over 5mA and a dose of 5×1015 /cm2.

Tem analysis of multiple-energy arsenic implanted and Rta'd silicon

1987 ◽  
Vol 45 ◽  
pp. 246-247
Author(s):  
R.A. Herring
Keyword(s):  
Device Fabrication ◽  
High Concentration ◽  
Tem Analysis ◽  
Defect Clusters ◽  
High Fluences ◽  
Small Defect ◽  
Before And After ◽  
The Matrix ◽  
The Difference ◽  
Factor Type

Rapid thermal annealing (RTA) of ion-implanted Si is important for device fabrication. The defect structures of 2.5, 4.0, and 6.0 MeV As-implanted silicon irradiated to fluences of 2E14, 4E14, and 6E14, respectively, have been analyzed by electron diffraction both before and after RTA at 1100°C for 10 seconds. At such high fluences and energies the implanted As ions change the Si from crystalline to amorphous. Three distinct amorphous regions emerge due to the three implantation energies used (Fig. 1). The amorphous regions are separated from each other by crystalline Si (marked L1, L2, and L3 in Fig. 1) which contains a high concentration of small defect clusters. The small defect clusters were similar to what had been determined earlier as being amorphous zones since their contrast was principally of the structure-factor type that arises due to the difference in extinction distance between the matrix and damage regions.

Defect Annihilation in Czochralski-Grown Silicon During Out-Diffusion Process Probed with Variable-Energy Positron Beam

1992 ◽  
Vol 262 ◽  
Author(s):  
T. Kitano ◽  
L. Wei ◽  
Y. Tabuki ◽  
S. Tanigawa ◽  
H. Mikoshiba
Keyword(s):  
High Temperature ◽  
Diffusion Process ◽  
Grown Crystal ◽  
Positron Beam ◽  
Defect Concentration ◽  
Energy Beam ◽  
Oxygen Cluster ◽  
Variable Energy ◽  
Oxygen Atoms

ABSTRACTThe defect annihilation in CZ-crystal was first detected during the process of oxygen out-diffusion, by the positron measurements with a variable-energy beam. The defects, which were related to oxygen atoms such as oxygen cluster, were mainly annihilated at the high temperature, ex., 1150°C. The defect concentration was decreasing down to one tenth, compared with that for an as-grown crystal.

Defect Formation by Ion Implantation in Cz-Si Studied by a Monoenergetic Positron Beam

1992 ◽  
Vol 262 ◽  
Author(s):  
A. Uedono ◽  
Y. Ujihira ◽  
L. Wei ◽  
Y. Tabuki ◽  
S. Tanigawa ◽  
...  
Keyword(s):  
Oxygen Vacancy ◽  
Ion Implantation ◽  
Defect Formation ◽  
Positron Beam ◽  
Low Energy ◽  
Doppler Broadening ◽  
Positron Energy ◽  
Annealing Experiments ◽  
Incident Positron ◽  
Ion Implanted

ABSTRACTVacancy-type defects in ion implanted Si were studied by a monoenergetic positron beam. The depth-distributions of the defects were obtained from measurements of Doppler broadening profiles of the positron annihilation as a function of incident positron energy. The results showed that a size of vacany-clusters introduced by 150-keV P+-ion implantation was found to be smaller than that introduced by 2-MeV P+-ion implantation. This was attributed to an overlap of collision cascades in low-energy (150 keV) ion implanted specimens. From isochronal annealing experiments for 80-keV B+- and 150-keV P+-ion implanted specimens, the defected region was removed by 1200 °C annealing, however, for 2-MeV P+-implanted specimen, two-types of oxygen-vacancy complexes were found to coexist even after 1200 °C annealing.

scholarly journals Corrosion Characteristics of Copper in Malaysian Bioethanol and Gasoline Blends

2013 ◽  
Vol 467 ◽  
pp. 122-126 ◽  
Author(s):  
T. Saravana Kannan ◽  
C. Piraiarasi ◽  
Abu Saleh Ahmed ◽  
Ani Farid Nasir
Keyword(s):  
Chemical Properties ◽  
Optical Microscope ◽  
Acid Number ◽  
Morphological Properties ◽  
Engine Fuel ◽  
High Concentration ◽  
Total Acid ◽  
Hardness Tester ◽  
Fuel Blends ◽  
Before And After

The present study aims to investigate the corrosion characteristics of copper commonly encountered in the spark ignition (SI) engine fuel system with Malaysian bioethanol and gasoline blends. Static immersion tests in E0 (gasoline), E10 and E85 were carried out at room temperature for 1320 h. Mechanical, physical and chemical properties of copper was investigated before and after immersion tests. Investigations were carried out on change in morphological properties using optical microscope; change in chemical structure using FTIR; change in mass and volume by weight loss measurement; hardness changes using universal hardness tester; and change of chemical properties of the fuel blends using total acid number titration method. The test results showed that corrosion of copper was increased with the high concentration of ethanol in the blends.

Isochronal annealing studies on 1.1 MeV Fe ion irradiated RAFM steel using variable energy slow positron beam

2017 ◽  
Author(s):  
Renjith Ramachandran ◽  
C. David ◽  
R. Rajaraman ◽  
S. Abhaya ◽  
B. K. Panigrahi ◽  
...  
Keyword(s):  
Positron Beam ◽  
Isochronal Annealing ◽  
Slow Positron ◽  
Rafm Steel ◽  
Variable Energy
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