On the Energetics of Extrinsic Defects in Si and their Role in Nonequilibrium Dopant Diffusion

2000 ◽  
Vol 610 ◽  
Author(s):  
Alain Claverie ◽  
Filadelfo Cristiano ◽  
Benjamin Colombeau ◽  
Nicholas Cowern
Keyword(s):  
Formation Energy ◽  
Ostwald Ripening ◽  
High Dose ◽  
Extended Defects ◽  
Dislocation Loops ◽  
Dynamical Equilibrium ◽  
Defect Interactions ◽  
Small Clusters ◽  
Dose Levels ◽  
Extrinsic Defects

AbstractIn this paper, we discuss the mechanisms by which small clusters evolve through “magic” sizes into {113} defects and then, at sufficiently high dose levels, transform into dislocation loops of two types. This ripening process is mediated by the interchange of free Si(int)s between different extended defects, leading to a decrease of their formation energy. The calculation of the supersaturation of free Si-interstitials in dynamical equilibrium with these defects shows a hierarchy of levels of nonequilibrium diffusion, ranging from supersaturations S of about 106 in the presence of small clusters, through 103 in the presence of {113} defects, to S in the range 100 down to 1 as loops are formed, evolve and finally evaporate. A detailed analysis of defect energetics has been carried out and it is shown that Ostwald ripening is the key concept for understanding and modelling defect interactions during TED of dopants in silicon.

Thermal Evolution of Extrinsic Defects in Ion Implanted Silicon: Current Understanding and Modelling

2002 ◽  
Vol 717 ◽  
Author(s):  
Fuccio Cristiano ◽  
Benjamin Colombeau ◽  
Bernadette de Mauduit ◽  
Caroline Bonafos ◽  
Gerard Benassayag ◽  
...  
Keyword(s):  
Ostwald Ripening ◽  
Thermal Evolution ◽  
Extensive Study ◽  
Extended Defects ◽  
Experimental Conditions ◽  
Annealing Conditions ◽  
Physically Based ◽  
Free Interstitial ◽  
Extrinsic Defects ◽  
Ion Implanted

AbstractWe present an extensive study of the thermal evolution of the extended defects found in ion implanted Si as a function of annealing conditions. We will first review their structure and energetics and show that the defect kinetics can be described by an Ostwald ripening process whereby the defects exchange Si atoms and evolve in size and type to minimise their formation energy. Finally, we will present a physically based model to predict the evolution of extrinsic defects during annealing through the calculation of defect densities, size distributions, number of clustered interstitials and free-interstitial supersaturation. We will show some successful applications of our model to a variety of experimental conditions and give an example of its predictive capabilities at ultra low implantation energies.

Atomistic simulations of extrinsic defects evolution and transient enhanced diffusion in silicon

2001 ◽  
Vol 669 ◽  
Author(s):  
A. Claverie ◽  
B. Colombeau ◽  
F. Cristiano ◽  
A. Altibelli ◽  
C. Bonafos
Keyword(s):  
Ostwald Ripening ◽  
Physical Modelling ◽  
Defect Layer ◽  
Low Energy ◽  
Atomistic Simulations ◽  
Correct Prediction ◽  
Dislocation Loops ◽  
Enhanced Diffusion ◽  
Loss Term ◽  
Extrinsic Defects

ABSTRACTWe have implemented an atomistic simulation of the Ostwald ripening of extrinsic defects (clusters, {113}'s and dislocation loops) which occurs during annealing of ion implanted silicon. Our model describes the concomitant time evolution of the defects and of the supersaturation of Si interstitial atoms in the region. It accounts for the capture and emission of these interstitials to and from extrinsic defects (defined by their formation energy) of sizes up to thousands of atoms and includes a loss term due to the interstitial flux to the surface. This model reproduces well the dissolution of {113} defects in Si implanted wafers. We have subsequently studied the characteristics of TED in the case of B implantation at low and ultra low energy. In such cases, the distance between the defect layer and the surface plays a crucial role in determining the TED decay time. The simulations show that defect dissolution occurs earlier and for smaller sizes in the ultra-low energy regime. Under such conditions, TED is mostly characterized by its “pulse” component which takes place at the very beginning of the anneal, probably during the ramping up. In summary, we have shown that the physical modelling of the formation and of the growth of extrinsic defects leads to a correct prediction of the “source term” of Si interstitials and at the origin of TED.

A Physically Based Modeling of Boron TED in Amorphised Si

2000 ◽  
Vol 610 ◽  
Author(s):  
Evelyne Lampin ◽  
Vincent Senez ◽  
Alain Claveriel
Keyword(s):  
Ostwald Ripening ◽  
Physically Based Modeling ◽  
Extended Defects ◽  
Dislocation Loops ◽  
Boron Diffusion ◽  
Experimental Conditions ◽  
Physically Based ◽  
Free Interstitial ◽  
Recombination Velocity ◽  
Process Simulator

AbstractWe have developed a physically based modeling of TED of implanted boron in amorphised Si. The simulation starts with a supersaturation of Si free interstitials located below the amorphous/crystalline interface which, upon annealing, tend to diffuse out or to precipitate in the form of extended defects (clusters, {113}s, dislocation loops). The modeling of the nucleation and growth of these defects is divided into three distinct stages: the nucleation, the “pure growth” and the Ostwald ripening. This system can interact with a surface (characterized by a given recombination velocity for Si interstitials) only after the SPE regrowth is completed. Implementation of this model into a process simulator allows to describe the isothermal and isochronal evolutions of the sizes and of the densities of dislocation loops in agreement with TEM observations. Assuming that boron diffusion is caused by the concomitant time and space variations of the free interstitial supersaturation in the wafer, TED can be accurately predicted for a variety of experimental conditions.

Stress-Related Defects in Implanted Locos + Trench - Isolated Structures

1992 ◽  
Vol 262 ◽  
Author(s):  
Barbara Vasquez ◽  
N. David Theodore
Keyword(s):  
Stress Fields ◽  
High Dose ◽  
Extended Defects ◽  
Dislocation Loops ◽  
Defect Engineering ◽  
Local Oxidation ◽  
Trench Isolation ◽  
And Behavior ◽  
Dislocation Sources ◽  
Reducing Stress

ABSTRACTPoly-buffered local-oxidation of silicon + trench-isolation (PBLT) is a technique being explored for device isolation. In an earlier study, we had reported the presence of dislocations associated with a combination of high-dose (∼5E14 cm2) phosphorous implants and PBLT isolation. In the present study, the behavior of extended defects present in the structures is analyzed in greater detail. The origin and behavior of the defects is modelled to explore potential mechanisms to explain the observations. Implantation induced dislocation-loops interact with stress fields associated with PBLT isolation-trenches. Some of the implant loops (in the presence of a stress field) transform to dislocation sources which then create glide dislocations in the structures. Strategies for defect engineering are discussed, including reducing implant-induced damage (lowering the implant dose) or reducing stress fields (by moving the edge of the implanted region away from the trench). Defect densities can be reduced or eliminated.

Device Parametric Shift Mechanism Caused by Boron Halo Redistribution Resulting from Dose Rate Dependence of SDE Implant

2005 ◽  
Vol 864 ◽  
Author(s):  
Ukyo Jeong ◽  
Jinning Liu ◽  
Baonian Guo ◽  
Kyuha Shim ◽  
Sandeep Mehta
Keyword(s):  
Surface Region ◽  
Amorphous Region ◽  
Amorphous Layer ◽  
High Dose ◽  
Extended Defects ◽  
Dislocation Loops ◽  
Near Surface ◽  
Enhanced Diffusion ◽  
Dose Rates ◽  
Pile Up

AbstractChange in dopant diffusion was observed for Arsenic source drain extension (SDE) implants when they were performed at various dose rates. The high dose SDE implant amorphizes the surface of the silicon substrate and the thickness of the amorphous layer is strongly influenced by the rate of dopant bombardment. It is well known that the ion implantation process introduces excess interstitials. While the amorphous region is completely re-grown into single crystal during subsequent anneal without leaving behind extended defects, interstitials that are injected beyond the amorphous layer lead to formation of {311} defects or dislocation loops in the end of range region. During thermal processing, these extended defects dissolve, release interstitials, which in turn lead to transient enhanced diffusion of underlying Boron halo dopant. Dopant depth profiles measured by SIMS revealed different amount of Boron pile-up in the near surface region, corresponding to different SDE implant dose rates. In CMOS devices, this surface pile-up would correlate with a Boron pile-up in the channel region that would lead to a shift in transistor characteristics. Through this investigation, we were able to explain the mechanism causing device characteristics shift resulted from SDE implant with the same dose and energy but different dose rates.

Effects of piperonyl butoxide on spontaneous behavior in F1-generation mice

2009 ◽  
Vol 25 (7) ◽  
pp. 489-497 ◽  
Author(s):  
Toyohito Tanaka ◽  
Osamu Takahashi ◽  
Shinshi Oishi ◽  
Akio Ogata
Keyword(s):  
Dose Group ◽  
Female Offspring ◽  
Piperonyl Butoxide ◽  
High Dose Group ◽  
High Dose ◽  
Adult Females ◽  
Developmental Parameters ◽  
Spontaneous Behavior ◽  
Dose Levels ◽  
F1 Generation

Piperonyl butoxide was given in the diet to provide levels of 0 (control), 0.02%, 0.06%, and 0.18% from 5 weeks of age of the F0 generation to 12 weeks of age of the F1 generation in mice. Select reproductive and neurobehavioral parameters were then measured. In exploratory behavior in the F0 generation, vertical time of adult females increased significantly in a dose-related manner. In behavioral developmental parameters, cliff avoidance was delayed significantly in the high-dose group in male offspring, and this effect was significantly dose-related. In female offspring, surface righting was significantly delayed in the high-dose group, and this effect was significantly dose-related. In spontaneous behavior in the F1 generation, females showed more activities in some variables in the high-dose group. Dose levels of piperonyl butoxide used in the present study produced several adverse effects in neurobehavioral parameters in mice.

Formation of Oxide Layers by High Dose Implantation into Silicon

1983 ◽  
Vol 27 ◽  
Author(s):  
S.S. Gill ◽  
I. H. Wilson
Keyword(s):  
Oxide Layer ◽  
Single Crystal Silicon ◽  
High Dose ◽  
Surface Oxide Layer ◽  
Crystal Silicon ◽  
Implantation Energy ◽  
Oxygen Ions ◽  
Oxygen Profile ◽  
Dose Levels ◽  
Very High

ABSTRACTSingle crystal silicon was implanted with 80, 120, 160 and 240 keV oxygen ions. Rutherford backscattering (RBS) analysis was used to obtain the implanted oxygen profile and the oxygen to silicon ratio in the implanted layer for doses in the range 1016 to 1.5 × 1018 O2+ cm−2 for room temperature implants. The depth and the thickness of the buried oxide layer has been measured as a function of implantation energy and oxygen dose. Chemical formation of stoichiometric SiO2 was confirmed by infra-red (IR) spectroscopy. Both RBS and IR indicate that once a surface oxide layer is formed for very high dose levels, the layer thickness decreases with increasing implanted dose beyond a critical dose level.

One-generation reproduction toxicity study of Dithane M-45 (mancozeb) and lead acetate

2002 ◽  
Vol 50 (3) ◽  
pp. 365-371 ◽  
Author(s):  
L. Várnagy ◽  
P. Budai ◽  
E. Molnár ◽  
Keyword(s):  
Body Weight ◽  
Lead Acetate ◽  
Clinical Symptoms ◽  
Reproductive Toxicity ◽  
The Body ◽  
High Dose ◽  
Lactation Period ◽  
Treatment Groups ◽  
Body Weight Increase ◽  
Dose Levels

The reproductive toxicity of lead acetate and of a fungicide formulation (Dithane M-45) containing 80% mancozeb was studied on rats. Lead acetate was applied in the feed in the following dose groups: control, 1,000, 5,000 and 10,000 mg/kg of diet. The three treatment groups received, in addition to the above doses of lead acetate, 4,500 mg/kg Dithane M-45 in the diet. The method was based on the OECD Guideline for Testing of Chemicals No. 415 (1981). Clinical symptoms and mortality were not found in the parent generation. The body weight of female animals decreased significantly before the pregnancy period. This tendency was also seen in males after the combination treatment. At the two high dose levels a remarkable body weight increase was seen in the female animals during the lactation period. As a result of treatment, decreased body weight of offspring was measured during the lactation period. No gross pathological changes were seen. Histological examination showed general tubulonephrosis in the experimental animals. It can be established that the administration of Dithane M-45 did not enhance the reproductive toxicity of lead acetate.

scholarly journals Lack of Neuropathological Changes in Rats Administered Tedizolid Phosphate for Nine Months

2014 ◽  
Vol 59 (1) ◽  
pp. 475-481 ◽  
Author(s):  
Michael J. Schlosser ◽  
Hiromi Hosako ◽  
Ann Radovsky ◽  
Mark T. Butt ◽  
Dragomir Draganov ◽  
...  
Keyword(s):  
Body Weight ◽  
Optic Nerve ◽  
Body Weight Gain ◽  
Maximum Tolerated Dose ◽  
High Dose ◽  
Once Daily ◽  
Clinical Observations ◽  
Activity Measures ◽  
Dose Levels ◽  
Neurobehavioral Effects

ABSTRACTTedizolid, a novel oxazolidinone antibacterial, was administered to Long Evans rats by oral gavage once daily for up to 9 months at doses near the maximum tolerated dose (MTD) to evaluate for potential neurotoxicity. Mean plasma exposures of tedizolid at the low-, medium-, and high-dose levels (7.5, 15, and 30 mg/kg of body weight/day for males; 2.5, 5, and 10 mg/kg/day for females) were similar between males and females and were 1.8-, 3.9-, and 8.0-fold greater than exposures in patients at the therapeutic dose (200 mg once daily). Evaluated endpoints included survival, clinical observations, body weight, and food consumption. At 1, 3, 6, and 9 months, ophthalmic examinations, functional observational batteries, and locomotor activity measures were conducted, brain weights/sizes were recorded, and perfusion-fixed tissues were collected from 12 rats/sex/group/time point. A detailed morphological assessment was conducted on brain, eyes, optic nerve/tract, spinal cord, peripheral nerves (includes sciatic, sural, tibial, peroneal, trigeminal), and skeletal muscle. At the end of 9 months, less body weight gain was seen in high-dose males (−6.7%) and females (−5.8%) compared with that seen in controls. There were no tedizolid-related adverse neurobehavioral effects or tedizolid-related histopathologic changes in the central/peripheral nervous systems, including the optic nerve. Results of this study indicate that tedizolid was not neurotoxic when administered long term to pigmented rats at doses near the MTD, which were up to 8-fold higher than the human therapeutic exposure.

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