Behavior Of The Potential N-Type Dopants P And As In Diamondafter Low Dose Ion Implantation

1996 ◽  
Vol 442 ◽  
Author(s):  
H. Hofsäss ◽  
M. Dalmer ◽  
M. Restle ◽  
C. Ronning ◽  
K. Bharuth-Ram ◽  
...  

AbstractWe have studied the lattice sites of P and As impurities in natural IIa diamond after room temperature ion implantation at very low doses of 1011 P/cm2 and ≤ 1013 As/cm2 and subsequent annealing. We implanted radioactive 33P and 73Se/73As probe atoms and used the sensitive emission channeling technique to determine the impurity lattice sites. In this technique the channeling effects of emitted decay electrons are measured for different crystal axes. By comparison with calculated electron emission distributions the fractions of emitter atoms on different lattice sites can be quantitatively determined. After annealing of the implanted samples above 900°C we find high substitutional fractions of 70 ± 10 % for 33P and 55 ± 5 % for 73As.

1983 ◽  
Vol 27 ◽  
Author(s):  
J.C. Soares ◽  
A.A. Melo ◽  
M.F. DA Silva ◽  
E.J. Alves ◽  
K. Freitag ◽  
...  

ABSTRACTLow and high dose hafnium imolanted beryllium samoles have been prepared at room temperature by ion implantation of beryllium commercial foils and single crystals. These samples have been studied before and after annealing with the time differential perturbed angular correlation method (TDPAC) and with Rutherford backscattering and channeling techniques. A new metastable system has been discovered in TDPAC-measurements in a low dose hafnium implanted beryllium foil annealed at 500°C. Channeling measurements show that the hafnium atoms after annealing, are in the regular tetrahedral sites but dislocated from the previous position occupied after implantation. The formation of this system is connected with the redistribution of oxygen in a thin layer under the surface. This effect does not take place precisely at the same temperature in foils and in single crystals.


1980 ◽  
Vol 43 (2) ◽  
pp. 114-118 ◽  
Author(s):  
S. YÜCEER ◽  
G. GÜNDÜZ

Irradiation preservation of Turkish kashar cheese and plain yogurt was studied using very low doses of Co-60 radiation. No side effects were observed below 0.15 Mrad. The number of bacteria killed was directly related to total dose up to 0.02 Mrad, then the effectiveness of the dose decreased. Coating cheese samples with a sorbic acid solution helped in reducing the number of bacteria by about 10–12% in irradiated samples. The shelf-life of irradiated samples stored at refrigerator temperature was almost the same as that of ones coated with sorbic acid but stored at room temperature. Mold formation in irradiated samples took three to four times longer than in nonirradiated ones. With plain yogurt the effect of total dose seemed to be the same as in cheese. Irradiation increased the shelf-life of yogurt three- to four-fold. Preservation by irradiation combined with refrigeration increased the shelf-life about five-fold.


1980 ◽  
Vol 2 ◽  
Author(s):  
Jack Washburn

ABSTRACTThe clustering of isolated interstitial silicon, implanted atoms, and vacant lattice sites produced by low temperature and room temperature ion implantation during subsequent annealing is reviewed. An electron microscope method for studying the kinetics of the amorphous to crystalline transformation in silicon is described. The technique is applied to measurement of the activation energy for interface migration and the formation of microtwins for different growth directions. A very brief review of the effects of laser annealing after ion implantation is included.


Author(s):  
C. R. Hills ◽  
G. J. Thomas ◽  
H. J. Stein

Previous investigators have shown that the surface regions of GaAs samples implanted at room temperature with 40-100 keV Ne ions become amorphous after a dose of the order of 1x1014ions cm-2. Their study also indicated that implantation above room temperature (35°-200°C) results in the retention of crystallinity even with fluences two to three orders of magnitude higher. Investigators using ion backscattering and optical absorption have shown that ion dose rate is also an important variable in ion implantation. In the present investigation, transmission microscopy has been used to further study the temperature and dose rate effects of ion implantation in GaAs. A number of {111} and {l00} single crystal GaAs samples have been implanted with 275 keV Xe ions to doses of 1015 and 1016 ions cm-2 at dose rates ranging from 2.5x1012 to 8.1xl012ions cm-2 sec-1.Low dose (1015ions cm-2) implantations at room temperature produced amorphous layers at all dose rates.


1997 ◽  
Vol 486 ◽  
Author(s):  
U. Wahl ◽  
J. G. Correia ◽  
G. Langouche ◽  
A. Vantomme ◽  
Isolde collaboration

AbstractWe report on the lattice location of 167Er in Si measured by conversion electron emission channeling. In both FZ and CZ Si, a high fraction of Er (>65%) occupies near-tetrahedral interstitial (T) sites directly following 60 keV room temperature implantation at doses of 6× 1012 cm−2 For higher doses, the as-implanted near-T fractions of Er visible by emission channeling are smaller, due to the beginning of amorphization. Following the recovery of implantation damage at 600°C, more than 70% of Er is found on near-T sites in both FZ and CZ Si. In FZ Si, Er exhibits a remarkable thermal stability and only prolonged annealing for several hours reduces the near-T fraction. On the other hand, annealing of CZ Si at 900°C for more than 10 minutes results in the majority of Er probes in sites of very low symmetry or disordered surroundings.


1997 ◽  
Vol 468 ◽  
Author(s):  
C. Running ◽  
M. Dalmer ◽  
M. Deicher ◽  
M. Restle ◽  
M. D. Bremser ◽  
...  

ABSTRACTSingle crystalline GaN-layers were implanted with radioactive 111In ions. The lattice location of the ions and the recovery of the implantation induced damage was studied using the emission channeling technique and perturbed-γγ-angular-correlation spectroscopy as a function of the annealing temperature. We find the majority of indium atoms on substitutional sites even directly after room temperature implantation, but within a heavily disturbed surrounding. During isochronal annealing treatments in vacuum, a gradual recovery of the implantation damage takes place between 873 K and 1173 K. After 1173 K annealing about 50 % of the In atoms occupy substitutional lattice sites with defect free surroundings.


1981 ◽  
Vol 17 (21) ◽  
pp. 817 ◽  
Author(s):  
H. Yamazaki ◽  
T. Honda ◽  
S. Miyazawa

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1955.1-1956
Author(s):  
T. Santiago ◽  
M. Voshaar ◽  
M. De Wit ◽  
P. Carvalho ◽  
M. Boers ◽  
...  

Background:The Glucocorticoid Low-dose Outcome in Rheumatoid Arthritis Study (GLORIA) is an international investigator-initiated pragmatic randomized trial designed to study the effects of low-dose glucocorticoids (GCs) in elderly patients with Rheumatoid Arthritis (RA).The research team is also committed to promote a better understanding of the risks and benefits of these drugs among health professionals and patients. In order to achieve these goals, it is important to assess the current ideas and concerns of patients regarding GCs.Objectives:To evaluate the current patient perspective on the efficacy and risks of GCs in RA patients who are or have been treated with GCs.Methods:Patients with RA completed an online survey (with 5 closed questions regarding efficacy and safety) presented in their native language. RA patients were recruited through a variety of patient organizations representing three continents. Patients were invited to participate through national patient organizations. In the USA, patients were also invited to participate through MediGuard.org. Participants were asked for their level of agreement on a 5-point Likert scale.Results:1344 RA patients with exposure to GCs, from Brazil, USA, UK, Portugal, Netherlands, Germany and 24 other countries** participated: 89% female, mean age (SD) 52 (14) years and mean disease duration 13 (11) years. The majority of participants (84%) had ≥10 years of education. The duration of GCs exposure was 1.6 (4.2) years. The majority of participants had read articles or pamphlets on the benefits or harms of GC therapy.Regarding GCs efficacy (table 1), high levels of endorsement were found: about 2/3 of patients considered that GCs as very useful in their case, more than half considered that GCs were effective even at low doses, and agreed that GC improved RA symptoms within days.Regarding safety (table 1), 1/3 of the participants reported having suffered some form of serious adverse events (AEs) due to GCs, and 9% perceived this as “life-threatening. Adverse events had a serious impact on quality of life, according to about 1/3 of the respondents.Conclusion:Patients with RA exposed to GC report a strong conviction that GCs are very useful and effective for the treatment of their RA, even at low doses. This is accompanied by an important prevalence of serious AEs. Understanding the patient perspective can improve shared decision-making between patient and rheumatologist.Funding statement:This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 634886.Disclosure of Interests:Tânia Santiago: None declared, Marieke Voshaar Grant/research support from: part of phd research, Speakers bureau: conducting a workshop (Pfizer), Maarten de Wit Grant/research support from: Dr. de Wit reports personal fees from Ely Lilly, 2019, personal fees from Celgene, 2019, personal fees from Pfizer, 2019, personal fees from Janssen-Cilag, 2017, outside the submitted work., Consultant of: Dr. de Wit reports personal fees from Ely Lilly, 2019, personal fees from Celgene, 2019, personal fees from Pfizer, 2019, personal fees from Janssen-Cilag, 2017, outside the submitted work., Speakers bureau: Dr. de Wit reports personal fees from Ely Lilly, 2019, personal fees from Celgene, 2019, personal fees from Pfizer, 2019, personal fees from Janssen-Cilag, 2017, outside the submitted work., Pedro Carvalho: None declared, Maarten Boers: None declared, Maurizio Cutolo Grant/research support from: Bristol-Myers Squibb, Actelion, Celgene, Consultant of: Bristol-Myers Squibb, Speakers bureau: Sigma-Alpha, Frank Buttgereit Grant/research support from: Amgen, BMS, Celgene, Generic Assays, GSK, Hexal, Horizon, Lilly, medac, Mundipharma, Novartis, Pfizer, Roche, and Sanofi., José Antonio P. da Silva Grant/research support from: Pfizer, Abbvie, Consultant of: Pfizer, AbbVie, Roche, Lilly, Novartis


1985 ◽  
Vol 56 ◽  
Author(s):  
T. NAKAMURA ◽  
S. KOMIYA ◽  
T. INATA ◽  
S. MUTO ◽  
S. HIYAMIZU

AbstractThe LO phonon frequency evaluated from Raman spectra identifies two compositional disordering mechanisms in GaAs-AlAs superlattices. For a high Se dose, the LO phonons of the Al0.5Ga0.5As alloy are observed from the asimplanted samples. That means the compositional disordering occurred just by Se implantation. The probable mechanism for this disordering is the implantation of Ga atoms into the AlAs layer and of Al atoms into the GaAs layer. The superlattices implanted at a low dose are disordered by the subsequent annealing. The mechanism is the enhanced interdiffusion of both Ga and Al atoms between the GaAs and AlAs layers by Se thermal diffusion.


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