The Effect of Vacancies Grown into Silicon on Gold Diffusion

1992 ◽  
Vol 262 ◽  
Author(s):  
R. K. Graupner ◽  
J. A. Van Vechten ◽  
P. Harwood ◽  
T. K. Monson
Keyword(s):  
Point Defects ◽  
Silicon Crystal ◽  
Silicon Surfaces ◽  
Vacuum System ◽  
Float Zone ◽  
Diffusion Temperature ◽  
High Concentrations ◽  
Gold Diffusion ◽  
Silicon Based ◽  
High Degree

ABSTRACTWe propose a generalized model for gold diffusion in silicon based on the effect of the high concentrations of vacancies and vacancy complexes in the as-grown silicon. The monovacancy profiles calculated using this model are identical to the substitutional gold profiles calculated using the kick-out model. We deposited Au on commercial float zone Si in a vacuum system after the Si had reached the diffusion temperature (1233 K) and had been annealed in various ways. Contrary to previously published reports, we find the electrically active Au with a nearly one-sided profile when the Au is deposited on samples which were preannealed in vacuum. We conclude that annealed silicon surfaces lack the imperfections needed to make them effective sources or sinks for vacancies or self-interstitials. We propose that this can cause a high degree of supersaturation in the as-grown silicon crystal since the point defects cannot annihilate at the surfaces to maintain equilibrium as the crystal is cooled.

Vacancy and oxygen behavior in carbon highly doped silicon

2001 ◽  
Vol 669 ◽  
Author(s):  
Pierre Lavéant ◽  
Peter Werner ◽  
Norbert Engler ◽  
Ulrich Goesele
Keyword(s):  
Point Defects ◽  
Bipolar Transistors ◽  
Carbon Doping ◽  
High Carbon ◽  
High Oxygen Concentration ◽  
High Carbon Concentration ◽  
Carbon Precipitation ◽  
High Concentrations ◽  
Co Precipitation ◽  
Silicon Based

ABSTRACTCarbon doping of silicon has gained interest since in high concentrations, carbon can reduce oreven suppress undesirable diffusion of the base dopant boron in silicon-based bipolar transistors. This behavior can only be understood in taking into account the silicon point defects i.e. vacancies and self-interstitials. In this work, we observe the oversaturation of vacancies produced by a high carbon concentration duringannealing. Experiments with a vacancy diffusing dopant, Antimony, are shown and prove this effect: in a carbon rich sample, the antimony diffusion is enhanced about 8 times compared to samples with a much lower carbonconcentration. We also investigate the carbon co-precipitation with oxygen. The carbon precipitation, asSiC, is facilitated with a high oxygen concentration. We explain this affinity by an exchange of point defects and a volume compensation. Finally, we show the precipitation of oxygen in relation to the vacancy oversaturation at 900°C.

Morphology and development of flow-pattern defect with extended nonagitated Secco etching

1994 ◽  
Vol 52 ◽  
pp. 868-869
Author(s):  
Y. Pan
Keyword(s):  
Flow Pattern ◽  
Silicon Crystal ◽  
Gate Oxide ◽  
Crystal Growth Rate ◽  
Etch Depth ◽  
Force Microscopy ◽  
Etch Pit ◽  
Float Zone ◽  
Atomic Force ◽  
Multiple Step

The D defect, which causes the degradation of gate oxide integrities (GOI), can be revealed by Secco etching as flow pattern defect (FPD) in both float zone (FZ) and Czochralski (Cz) silicon crystal or as crystal originated particles (COP) by a multiple-step SC-1 cleaning process. By decreasing the crystal growth rate or high temperature annealing, the FPD density can be reduced, while the D defectsize increased. During the etching, the FPD surface density and etch pit size (FPD #1) increased withthe etch depth, while the wedge shaped contours do not change their positions and curvatures (FIG.l).In this paper, with atomic force microscopy (AFM), a simple model for FPD morphology by non-crystallographic preferential etching, such as Secco etching, was established.One sample wafer (FPD #2) was Secco etched with surface removed by 4 μm (FIG.2). The cross section view shows the FPD has a circular saucer pit and the wedge contours are actually the side surfaces of a terrace structure with very small slopes. Note that the scale in z direction is purposely enhanced in the AFM images. The pit dimensions are listed in TABLE 1.

scholarly journals Proteolytic enzyme arbitrated antagonization of helminthiasis by Cinnamomum cappara leaf extract in Pheretima posthuma

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Kayeen Vadakkan ◽  
Meena K Cheruvathur ◽  
Anu S Chulliparambil ◽  
Famy Francis ◽  
Anu P Abimannue
Keyword(s):  
Leaf Extract ◽  
Anthelmintic Activity ◽  
Enzymatic Action ◽  
Local Areas ◽  
Hyperbolic Relation ◽  
Proteolytic Action ◽  
High Concentrations ◽  
High Degree ◽  
Morphological And Molecular Characterization ◽  
Burk Plot

Abstract Background There have been several studies carried out to irradiate Helminthiasis however very little research have been carried out where in the enzymatic activity of plants are exploited to antagonize infections. Here we are analyzing the anthelmintic activity of Cinnamomum cappara leaf extract against Pheretima posthuma complimented by proteolytic action. Results The fresh leaves of Cinnamomum cappara was collected from local areas of Thrissur during December 2019. Plants were identified and authenticated by morphological and molecular characterization. The enzymatic action was analyzed by plotting Lineweaver–Burk plot which suggested that the extract possess the Km 185.77 μM for casein as substrate and obeyed Michaelis–Menten kinetics with typical hyperbolic relation with enzyme and increasing concentration of substrate. The effect of extract upon study subject was in directly proportional with concentration of antagonist where higher activities were obtained in high concentrations. The anatomical and histological studies suggested that the activity of extract was due to the degradation of muscular bundle of subject that resulted in the leakage of ceolomic fluid. Conclusions Cinnamomum cappara leaf extract possessed high degree of protease intervened anthelmintic activity against Pheretima posthuma. As the study subject show immense morphological and physiological resemblance with all other helminthic parasites, this results shall be adopted to further clinical and pharmacological applications.

Float-Zone silicon crystal growth at reduced RF frequencies

2012 ◽  
Vol 360 ◽  
pp. 43-46 ◽  
Author(s):  
H.-J. Rost ◽  
R. Menzel ◽  
A. Luedge ◽  
H. Riemann
Keyword(s):  
Crystal Growth ◽  
Silicon Crystal ◽  
Float Zone

The isolation of nucleic acids from woody tissue using dimethyl sulfoxide

1972 ◽  
Vol 50 (5) ◽  
pp. 1085-1090 ◽  
Author(s):  
L. V. Gusta ◽  
V. C. Runeckles
Keyword(s):  
Nucleic Acids ◽  
Experimental Evidence ◽  
Dimethyl Sulfoxide ◽  
Ribonuclease Activity ◽  
Woody Tissue ◽  
Bark Tissue ◽  
High Concentrations ◽  
High Degree

A procedure is described for the isolation of nucleic acids from apple bark tissue using dimethyl sulfoxide. Nucleic acids isolated by this method are high in yield, and exhibit a high degree of purity as evidenced by their spectra. Experimental evidence is given to show that extraction of the tissue with dimethyl sulfoxide before the extraction of nucleic acids removes protein and pigments. Little or no ribonuclease activity could be detected in apple bark tissue after extraction with dimethyl sulfoxide. Ribonuclease activity was shown to be strongly inhibited by high concentrations of dimethyl sulfoxide.

scholarly journals Trace-element geochemistry of diamond-hosted olivine inclusions from the Akwatia Mine, West African Craton: implications for diamond paragenesis and geothermobarometry

2019 ◽  
Vol 174 (12) ◽  
Author(s):  
J. C. M. De Hoog ◽  
T. Stachel ◽  
J. W. Harris
Keyword(s):  
Trace Element ◽  
West African ◽  
Mantle Xenoliths ◽  
Trace Element Geochemistry ◽  
Element Geochemistry ◽  
West African Craton ◽  
Trivalent Cations ◽  
Mantle Processes ◽  
High Concentrations ◽  
High Degree

AbstractTrace-element concentrations in olivine and coexisting garnets included in diamonds from the Akwatia Mine (Ghana, West African Craton) were measured to show that olivine can provide similar information about equilibration temperature, diamond paragenesis and mantle processes as garnet. Trace-element systematics can be used to distinguish harzburgitic olivines from lherzolite ones: if Ca/Al ratios of olivine are below the mantle lherzolite trend (Ca/Al < 2.2), they are derived from a harzburgitic mantle source, and syngenetic garnets are without exception subcalcic G10 garnets. For harzburgitic olivines that cannot be identified this way, Na and Ca contents can be used: olivine inclusions with < 60 µg/g Na and Na/Al < 0.7 are all harzburgitic, whereas those with > 300 µg/g Ca or > 60 µg/g Na are lherzolitic. Conventional geothermobarometry indicates that Akwatia diamonds formed and resided close to a 39 mW/m2 conductive geotherm. A similar value can be derived from Al in olivine geothermometry, with TAl-ol ranging from 1020 to 1325 °C. Ni in garnet temperatures is on average somewhat higher (TNi-grt = 1115–1335 °C) and the correlation between the two thermometers is weak, which may be not only due to the large uncertainties in the calibrations, but also due to disequilibrium between inclusions from the same diamond. Calcium in olivine should not be used as a geothermobarometer for harzburgitic olivines, and often gives unrealistic P–T estimates for lherzolitic olivine as well. Diamond-hosted olivine inclusions indicate growth in an extremely depleted (low Ti, Ca, Na, high Cr#) environment with no residual clinopyroxene. They are distinct from olivines from mantle xenoliths which show higher, more variable Ti contents and lower Cr#. Hence, most olivine inclusions in Akwatia diamonds escaped the refertilisation processes that have affected most mantle xenoliths. Lherzolitic inclusions are probably the result of refertilisation after undergoing high-degree melting first. Trivalent cations appear to behave differently in harzburgitic diamond-hosted olivine inclusions than lherzolitic inclusions and olivine from mantle xenoliths. Some divalent chromium is predicted to be present in most olivine inclusions, which may explain high concentrations up to 0.16 wt% Cr2O3 observed in some diamond inclusions. Strong heterogeneity of Cr, V and Al in several inclusions may also result in apparent high Cr contents, and is probably due to late-stage processes during exhumation. However, in general, diamond-hosted olivine inclusions have lower Cr and V than expected compared to mantle xenoliths. Reduced Na activity in depleted harzburgites limits the uptake of Cr, V and Sc via Na–M3+ exchange. In contrast, Al partitioning in harzburgites is not significantly reduced compared to lherzolites, presumably due to uptake of Al in olivine by Al–Al exchange.

Changes of DLTS Spectrum with Gold Concentration and Gold-Diffusion Temperature in N-Type Silicon

1988 ◽  
Vol 27 (Part 1, No. 9) ◽  
pp. 1778-1779 ◽  
Author(s):  
Masami Morooka ◽  
Hajime Tomokage ◽  
Masayuki Yoshida
Keyword(s):  
Gold Concentration ◽  
Dlts Spectrum ◽  
Type Silicon ◽  
Diffusion Temperature ◽  
Gold Diffusion

Ecology of Australian Chats (Epthianura Gould): Aridity, Electrolytes and Water Economy.

1977 ◽  
Vol 25 (4) ◽  
pp. 673 ◽  
Author(s):  
CK Williams ◽  
AR Main
Keyword(s):  
Drinking Water ◽  
Arid Regions ◽  
Body Water ◽  
Seasonal Movements ◽  
Ambient Temperatures ◽  
Complex Interactions ◽  
Low Concentrations ◽  
Access To Water ◽  
High Concentrations ◽  
High Degree

The four species of Australian chats differentially occupy semiarid and arid regions where surface water commonly contains high concentrations of electrolytes, especially during the summer. The effects of variations in ambient temperature and salinity of drinking water on nutrition, water and electrolyte balances were compared between three species of chats in a split-plot, factorial design. The homeostatic responses revealed very complex interactions between thermoregulation, nutrition, and balances of electrolytes and water. All species have very low tolerance of electrolytes in the drinking water. Ingested electrolytes are not stored but are rapidly excreted in low concentrations at the expense of body water. Survival of chats in arid regions depends on a high degree of selectivity in avoiding water sources with even moderate concentrations of electrolytes. This avoidance is achieved by nomadism and seasonal movements to areas of recent rainfall, thereby increasing the access to water with low concentrations of electrolytes. The ability of the more xeric species to occupy regions of greater aridity cannot be explained by enhanced abilities to excrete electrolytes in high concentrations. The three species studied excrete electrolytes in similar, low concentrations. The more xeric species possess an advantage in water and electrolyte balances through lower evaporative losses of body water, especially at high ambient temperatures.

Gas Phase Phosphorus Heavily-Doped FZ Silicon Thermal Field Design and Growth Method

2012 ◽  
Vol 430-432 ◽  
pp. 929-932
Author(s):  
Xue Nan Zhang ◽  
Jian Hong Li ◽  
Yu Tian Wang ◽  
Chang Xu Zhang ◽  
Chun Geng Yang ◽  
...  
Keyword(s):  
Gas Phase ◽  
Thermal Field ◽  
Cooling System ◽  
Silicon Crystal ◽  
Substrate Material ◽  
Low Oxygen ◽  
Float Zone ◽  
Growth Method ◽  
Resistivity Variation ◽  
Heavily Doped

This paper introduces the fabrication method of a kind of gas phase phosphorus heavily-doped float zone (FZ) silicon, including thermal field design (electromagnetic copper coil with double water cooling system). This method solves the problems during the pulling process of heavily-doped FZ silicon crystal of phosphorus doped. The gas phase phosphorus heavily-doped FZ silicon crystal using this methods with low oxygen content (less than 0.2ppma),low radial resistivity variation (less than 10%), low resistivity (the minimum of 0.002 ohm.cm), and is good to meet the transient voltage suppressor (TVS) for silicon substrate material requirements.

Sol-gel-based doped granulated silica for the rapid production of optical fibers

2014 ◽  
Vol 28 (12) ◽  
pp. 1442010 ◽  
Author(s):  
Valerio Romano ◽  
Soenke Pilz ◽  
Dereje Etissa
Keyword(s):  
Optical Fibers ◽  
Sol Gel ◽  
Cost Effective ◽  
Recent Past ◽  
Fiber Preform ◽  
Microstructured Optical Fibers ◽  
Rapid Production ◽  
Glass Tubes ◽  
High Concentrations ◽  
High Degree

In the recent past we have studied the granulated silica method as a versatile and cost effective way of fiber preform production. We have used the sol-gel technology combined with a laser-assisted remelting step to produce high homogeneity rare earth or transition metal-activated microsized particles for the fiber core. For the fiber cladding pure or index-raised granulated silica has been employed. Silica glass tubes, appropriately filled with these granular materials, are then drawn to fibers, eventually after an optional quality enhancing vitrification step. The process offers a high degree of compositional flexibility with respect to dopants; it further facilitates to achieve high concentrations even in cases when several dopants are used and allows for the implementation of fiber microstructures. By this "rapid preform production" technique, that is also ideally suited for the preparation of microstructured optical fibers, several fibers have been produced and three of them will be presented here.

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