Gettering by Overpressurized Bubbles Induced by High-Energy-He-Implantation In Silicon

2002 ◽  
Vol 719 ◽  
Author(s):  
Gabrielle Regula ◽  
Rachid El Bouayadi ◽  
Bernard Pichaud ◽  
Sylvie Godey ◽  
Romain Delamare ◽  
...  
Keyword(s):  
High Energy ◽  
Nuclear Reaction Analysis ◽  
Dislocation Loops ◽  
Metal Impurities ◽  
Implantation Depth ◽  
Unexpected Consequence ◽  
Section Electron ◽  
Induced Defects ◽  
Secondary Ion ◽  
Section Electron Microscopy

AbstractSilicon samples were implanted with He ions at 1.6 MeV using doses ranging from 1×1016 cm-2 to 1×1017cm-2 with different fluxes (0.4νA/cm2 - 2.0νA/cm2) and annealed at high (1000°C) and low temperatures (800°C). The implantation induced-defect structure and their distribution in the depth of the sample were studied by cross section electron microscopy (XTEM). An unexpected consequence of the flux on the defect population and density was found solely for 2×1016 cm-2, which is the upper threshold to get nano-bubbles at such large implantation depth. Nuclear Reaction Analysis (NRA) were performed to measure the ratio of He remaining in the bubbles as a function of time and temperature anneal. Some samples were gold or nickel diffused at temperatures ranging from 870°C to 1050°C prior to He implantation. The gettering efficiency of the implantation-induced defects was measured by secondary ion mass spectroscopy (SIMS), after a high temperature getter annealing. SIMS profiles exhibit a shape and a width closely related to the presence of the defects (observed by XTEM) which are very efficient sinks for all kinds of metal impurities. The bubbles were found to be more efficient traps than the dislocation loops.

Evolution Of Defects Induced By High Energy He Implantation In Gold-Diffused Silicon

2001 ◽  
Vol 669 ◽  
Author(s):  
R. El Bouayadi ◽  
G. Regula ◽  
B. Pichaud ◽  
M. Lancin ◽  
J. J. Simon ◽  
...  
Keyword(s):  
Deep Level ◽  
Critical Diameter ◽  
High Energy ◽  
High Concentration ◽  
High Metal ◽  
Different Temperatures ◽  
Section Electron ◽  
Transient Spectroscopy ◽  
Secondary Ion ◽  
Minority Carriers

ABSTRACTSilicon samples were gold-diffused at different temperatures, implanted with He ions at 1.6 MeVand then annealed at 1050°C for 2 hours. The implantation induced-defect structure and their distributionin the depth of the sample, studied by conventional and high resolution cross section electron microscopy (HRXTEM) depend on the gold level introduced in the wafer prior to the gettering process. A high concentration of gold in silicon seems to influence the defect configuration in the cavity zone. Indeed, gold chemisorbed atcavities can homogenize the surface energy of their planes in different orientations, and can increase the cavity critical diameter beyond they become facetted. Secondary ion mass spectroscopy (SIMS) profiles exhibit ashouldered shape and a width closely related to the presence of the defects (observed by XTEM) which are veryefficient sinks both for gold and copper atoms. Unfortunately, the electrical improvement of the material (checked by minority carriers diffusion length measurements MCDL) is not achieved by this gettering process, probably due to the high metal impurity concentrations remaining out of the gettering zone, to the presence of AuCu complexes and η-Cu3Si precipitates identified by deep level transient spectroscopy (DLTS)measurements and HRXTEM observations respectively.

scholarly journals Thermal Evolution of Deuterium in 4H-Sic

2002 ◽  
Vol 719 ◽  
Author(s):  
R. Delamare ◽  
E. Ntsoenzok ◽  
T. Sauvage ◽  
A. Shiryaev ◽  
A. van Veen ◽  
...  
Keyword(s):  
Room Temperature ◽  
Thermal Evolution ◽  
Thermal Desorption Spectroscopy ◽  
Analytical Techniques ◽  
Nuclear Reaction Analysis ◽  
Deuterium Content ◽  
Annealing Temperatures ◽  
Deuterium Concentration ◽  
Induced Defects ◽  
Secondary Ion

Abstract4H-SiC samples were implanted at room temperature with 30 keV D+ ions at a dose of 5×1016 D+/cm2. Nuclear reaction analysis (NRA) and secondary ion mass spectroscopy (SIMS) measurements were performed to study the deuterium profiles after subsequent annealing at 1000-1250°C for 10min.Also, analytical techniques: RBS/C and thermal desorption spectroscopy (TDS) were carried out to characterize the evolution of implantation induced defects upon annealing. According to the NRA measurements, no deuterium release was found in the sample annealed at 1000°C. However, increasing the temperature to 1150°C led to a 40% decrease of deuterium content. Similar results about the evolution of D profiles upon annealing have also been obtained by SIMS measurements. In addition, SIMS measurements show that the maximum of the deuterium concentration shifts to the surface. Deuterium desorption at annealing temperatures higher than 1000°C was further confirmed by TDS experiments. Results from RBS/C indicated that during the desorption of deuterium, the implantation induced damage was annealed. These results are discussed.

The Infection of Cells by Bullet-Shaped Viruses

1969 ◽  
Vol 27 ◽  
pp. 372-373
Author(s):  
Frederick A. Murphy ◽  
Alyne K. Harrison ◽  
Sylvia G. Whitfield
Keyword(s):  
Electron Microscopy ◽  
Physical Properties ◽  
Host Cell ◽  
Thin Section ◽  
Cultured Cells ◽  
Cell Infection ◽  
Thin Section Electron Microscopy ◽  
Section Electron ◽  
Section Electron Microscopy

The bullet-shaped viruses are currently classified together on the basis of similarities in virion morphology and physical properties. Biologically and ecologically the member viruses are extremely diverse. In searching for further bases for making comparisons of these agents, the nature of host cell infection, both in vivo and in cultured cells, has been explored by thin-section electron microscopy.

Normal Synaptonemal Complex and Abnormal Recombination Nodules in Two Alleles of the Drosophila Meiotic Mutant mei-W68

Genetics ◽  
2003 ◽  
Vol 163 (4) ◽  
pp. 1337-1356 ◽  
Author(s):  
Adelaide T C Carpenter
Keyword(s):  
Electron Microscopy ◽  
Synaptonemal Complex ◽  
High Frequency ◽  
Serial Section ◽  
The Other ◽  
Wild Type ◽  
Recombination Nodules ◽  
Section Electron ◽  
Serial Section Electron Microscopy ◽  
Section Electron Microscopy

Abstract The meiotic phenotypes of two mutant alleles of the mei-W68 gene, 1 and L1, were studied by genetics and by serial-section electron microscopy. Despite no or reduced exchange, both mutant alleles have normal synaptonemal complex. However, neither has any early recombination nodules; instead, both exhibit high numbers of very long (up to 2 μm) structures here named “noodles.” These are hypothesized to be formed by the unchecked extension of identical but much shorter structures ephemerally seen in wild type, which may be precursors of early recombination nodules. Although the mei-W68L1 allele is identical to the mei-W681 allele in both the absence of early recombination nodules and a high frequency of noodles (i.e., it is amorphic for the noodle phene), it is hypomorphic in its effects on exchange and late recombination nodules. The differential effects of this allele on early and late recombination nodules are consistent with the hypothesis that Drosophila females have two separate recombination pathways—one for simple gene conversion, the other for exchange.

Effects of Concurrent Co or Ti Silicidation on Transient Diffusion and End-of-Range Damage in Phosphorus Implanted Silicon

1992 ◽  
Vol 262 ◽  
Author(s):  
J.W. Honeycutt ◽  
J. Ravi ◽  
G. A. Rozgonyi
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Complete Removal ◽  
Dislocation Loops ◽  
Enhanced Diffusion ◽  
Depth Profiles ◽  
Enhanced Dissolution ◽  
Implantation Damage ◽  
Transmission Electron ◽  
Defect Behavior ◽  
Secondary Ion

ABSTRACTThe effects of Ti and Co silicidation on P+ ion implantation damage in Si have been investigated. After silicidation of unannealed 40 keV, 2×1015 cm-2 P+ implanted junctions by rapid thermal annealing at 900°C for 10–300 seconds, secondary ion mass spectrometry depth profiles of phosphorus in suicided and non-silicided junctions were compared. While non-silicided and TiSi2 suicided junctions exhibited equal amounts of transient enhanced diffusion behavior, the junction depths under COSi2 were significantly shallower. End-of-range interstitial dislocation loops in the same suicided and non-silicided junctions were studied by planview transmission electron microscopy. The loops were found to be stable after 900°C, 5 minute annealing in non-silicided material, and their formation was only slightly effected by TiSi2 or COSi2 silicidation. However, enhanced dissolution of the loops was observed under both TiSi2 and COSi2, with essentially complete removal of the defects under COSi2 after 5 minutes at 900°C. The observed diffusion and defect behavior strongly suggest that implantation damage induced excess interstitial concentrations are significantly reduced by the formation and presence of COSi2, and to a lesser extent by TiSi2. The observed time-dependent defect removal under the suicide films suggests that vacancy injection and/or interstitial absorption by the suicide film continues long after the suicide chemical reaction is complete.

Hb Neuilly-Sur-Marne, a New Human Hemoglobin Variant with Ser-Asp-Leu Inserted between α86(F7) Leu and α87(F8) His: Characterization by High-Energy Collision-Induced Dissociation Liquid Secondary Ion Mass Spectrometry and Low Energy Collision-Induced Dissociation Tandem Mass Spectrometry in An Ion Trap Fitted with a Nanospray Ionization Source

2000 ◽  
Vol 6 (2) ◽  
pp. 205-211 ◽  
Author(s):  
Danielle Promé ◽  
Jean-Claude Promé ◽  
Henri Wajcman ◽  
Jean Riou ◽  
Frédéric Galactéros ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Ion Trap ◽  
High Energy ◽  
Sequence Information ◽  
Energy Collision ◽  
Ionization Source ◽  
Nanospray Ionization ◽  
Singly Charged ◽  
Secondary Ion

Hemoglobin (Hb) Neuilly-sur-Marne is a new α-chain variant found during a systematic screening. Electrospray mass measurements showed the presence of an abnormal α-chain displaying a shift of +315 u relative to the normal value. Tryptic cleavage of this chain and molecular weight determination of the peptides indicated that the 315 u shift was located into the αT-9 peptide, the molecular weight of which is higher than 3000 Da. High-energy collision spectra of MH+ ions generated by liquid secondary ion mass spectrometry from the normal and abnormal αT-9 afforded mainly amino-terminal containing ions. They indicated that these two peptides have an identical amino acid sequence from their 1st to 25th residues, the mass increase being thus located beyond this point. Too few ions were formed to establish reliably the sequence forward. It was hypothesized that this mass shift could result from a repeated sequence since the sum of the mass of the three residues—leucine, serine and aspartic acid—preceding position 25 is exactly 315 u. To get sequence information above position 25, decomposition of multicharged species was attempted. An ion trap fitted with a nanospray ionization source was used. It produced mainly triply- and quadruply-charged ions. Decomposition of the triply-charged ion afforded a series of singly-charged Y-ions in the expected region, giving a readily interpretable sequence. It confirmed the insertion of a Ser-Asp-Leu sequence above position 25. Surprisingly, decomposition of the quadruply-charged molecular ion gave too few ions to provide sequence information in the expected region. Spectra were dominated by some multicharged Y ions arising from cleavages close to the amino end. Tandem mass spectrometry experiments were performed on the abundant Y303+ ion and produced again a singly-charged Y ion series in the suitable domain which confirmed the above result. In Hb Neuilly-sur Marne this insertion of the Ser-Asp-Leu residues. between positions α-86 and α-87 is very likely due to a slipped strand mispairing mechanism.

Effect of taxol on the interaction of tubulin with myosin filaments

1984 ◽  
Vol 62 (9) ◽  
pp. 878-884 ◽  
Author(s):  
Toshihiro Fujii ◽  
Tatsuo Suzuki ◽  
Akira Hachimori ◽  
Michiyo Fujii ◽  
Yoshiyuki Kondo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Skeletal Muscle ◽  
Atpase Activity ◽  
Cross Section ◽  
Molar Ratio ◽  
Tubulin Polymerization ◽  
Myosin Filaments ◽  
Thin Section Electron Microscopy ◽  
Section Electron ◽  
Section Electron Microscopy

The interaction between polymerized tubulin from porcine brain and myosin from rabbit skeletal muscle was examined. The addition of myosin to the solution of tubulin polymerized by taxol resulted in a remarkable increase in turbidity within a few minutes at 37 °C, and a dense and stable precipitate was formed. The maximal molar ratio of tubulin bound to myosin was calculated to be about 4, while the value was about 2 when 6S tubulin was used. Both podophyllotoxin and colchicine suppressed the taxol-dependent increase of the binding of tubulin to myosin, but only when they were preincubated with tubulin prior to addition of taxol. 6S tubulin inhibited with aetin-activated Mg2+-ATPase activity of myosin, and polymerized tubulin inhibited the Mg-ATPase more than 6S tubulin. Dense precipitates of tubulin and myosin were observed by thin-section electron microscopy. Microtubules were observed to be entangled in myosin filaments and single microtubules were occasionally surrounded by five myosin filaments in a cross section, similar to actin–myosin arrays in muscle. After incubation of tubulin with myosin, taxol was able to induce tubulin polymerization in the same way as it polymerized microtubules in the absence of myosin.

scholarly journals Dislocation Loop Generation Differences between Thin Films and Bulk in EFDA Pure Iron under Self-Ion Irradiation at 20 MeV

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2000
Author(s):  
Marcelo Roldán ◽  
Fernando José Sánchez ◽  
Pilar Fernández ◽  
Christophe J. Ortiz ◽  
Adrián Gómez-Herrero ◽  
...  
Keyword(s):  
Thin Films ◽  
Computational Models ◽  
Defect Formation ◽  
Ion Irradiation ◽  
Damage Zone ◽  
High Energy ◽  
Model Material ◽  
Dislocation Nucleation ◽  
Dislocation Loops ◽  
Experimental Conditions

In the present investigation, high-energy self-ion irradiation experiments (20 MeV Fe+4) were performed on two types of pure Fe samples to evaluate the formation of dislocation loops as a function of material volume. The choice of model material, namely EFDA pure Fe, was made to emulate experiments simulated with computational models that study defect evolution. The experimental conditions were an ion fluence of 4.25 and 8.5 × 1015 ions/cm2 and an irradiation temperature of 350 and 450 °C, respectively. First, the ions pass through the samples, which are thin films of less than 100 nm. With this procedure, the formation of the accumulated damage zone, which is the peak where the ions stop, and the injection of interstitials are prevented. As a result, the effect of two free surfaces on defect formation can be studied. In the second type of experiments, the same irradiations were performed on bulk samples to compare the creation of defects in the first 100 nm depth with the microstructure found in the whole thickness of the thin films. Apparent differences were found between the thin foil irradiation and the first 100 nm in bulk specimens in terms of dislocation loops, even with a similar primary knock-on atom (PKA) spectrum. In thin films, the most loops identified in all four experimental conditions were b ±a0<100>{200} type with sizes of hundreds of nm depending on the experimental conditions, similarly to bulk samples where practically no defects were detected. These important results would help validate computational simulations about the evolution of defects in alpha iron thin films irradiated with energetic ions at large doses, which would predict the dislocation nucleation and growth.

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