Point defect Supersaturation and Enhanced Diffusion in SPE Regrown Silicon.

1983 ◽  
Vol 27 ◽  
Author(s):  
S. J. Pennycook ◽  
J. Narayan ◽  
O. W. Holland
Keyword(s):  
Activation Energy ◽  
Point Defect ◽  
Solid Phase ◽  
High Concentration ◽  
Enhanced Diffusion ◽  
Transient Enhanced Diffusion ◽  
Migration Enthalpy

ABSTRACTTransient, greatly enhanced diffusion has been observed on annealing solid-phase-epitaxial (SPE) grown Si-Sb alloys. This is shown to be due to a high concentration of interstitials being trapped during SPE regrowth. The migration enthalpy, for diffusion of Sb by an interstitialcy mechanism was measured as 1.8 ± 0.2 eV. The interstitials eventually condensed into loops, marking the end of the transient. In a SPE grown Si-Bi alloy a similar transient enhanced diffusion was observed, with an activation energy of 2.0 ± 0.2 eV, but no loops formed.

A Comprehensive Model for Carbon Suppression of Boron Transient Enhanced Diffusion

2001 ◽  
Vol 669 ◽  
Author(s):  
Julie L. Ngau ◽  
Peter B. Griffin ◽  
James D. Plummer
Keyword(s):  
Point Defect ◽  
Recent Work ◽  
Comprehensive Model ◽  
Pairing Mechanism ◽  
Diffusion Behavior ◽  
Interstitial Carbon ◽  
Enhanced Diffusion ◽  
Transient Enhanced Diffusion ◽  
Single Temperature ◽  
Carbon Interstitial

ABSTRACTIn this work, the time evolution of B transient enhanced diffusion (TED) suppression due to the incorporation of 0.018% substitutional carbon in silicon was studied. The combination of having low C concentrations, which reduce B TED without completely eliminating it, and having diffused B profiles for several times at a single temperature provides much data upon which various models for the suppression of B TED can be tested. Recent work in the literature has indicated that the suppression of B TED in C-rich Si is caused by non-equilibrium Si point defect concentrations, specifically the undersaturation of Si self-interstitials, that result from the coupled out-diffusion of carbon interstitials via the kick-out and Frank-Turnbull reactions. Attempts to model our data with these two reactions revealed that the time evolved diffusion behavior of B was not accurately simulated and that an additional reaction that further reduces the Si self-inter- stitial concentration was necessary. In this work, we incorporate a carbon interstitial, carbon substitutional (CiCs) pairing mechanism into a comprehensive model that includes the C kick-out reaction, C Frank-Turnbull reaction, {311} defects, and boron interstitial clusters (BICs) and demonstrate that this model successfully simulates C suppression of B TED at 750 °C for anneal times ranging from 10 s to 60 min.

Modeling of TED Point Defect Paramater Extraction

2002 ◽  
Vol 717 ◽  
Author(s):  
Heidi Meyer ◽  
Scott T. Dunham
Keyword(s):  
Point Defect ◽  
Diffusion Capacity ◽  
Enhanced Diffusion ◽  
Self Diffusion ◽  
Transient Enhanced Diffusion ◽  
Two Factors

AbstractThe work investigates simple transient enhanced diffusion (TED) behavior, which is a reflection of the interstitial behavior in the system. The analysis shows that TED depends mainly on two factors: the intial demage profiles and the DICI product. We find that, based on these two inputs, the extent of TED can be accurately diffusion capacity (DICI) which is compared to values previously extracted from diffcusion and silicon self-diffusion experiments.

Fundamental Modeling of Transient Enhanced Diffusion through Extended Defect Evolution

1997 ◽  
Vol 469 ◽  
Author(s):  
A. H. Gencer ◽  
S. Chakravarthi ◽  
I. Clejan ◽  
S. T. Dunham
Keyword(s):  
Point Defect ◽  
Extended Defects ◽  
Dislocation Loops ◽  
Extended Defect ◽  
Enhanced Diffusion ◽  
Fundamental Model ◽  
Transient Enhanced Diffusion ◽  
Defect Evolution

Prediction of transient enhanced diffusion (TED) requires modeling of extended defects of many types, such as {311} defects, dislocation loops, boron-interstitial clusters, arsenic precipitates, etc. These extended defects not only form individually, but they also interact with each other through changes in point defect and solute concentrations. We have developed a fundamental model which can account for the behavior of a broad range of extended defects, as well as their interactions with each other. We have successfully applied and parameterized our model to a range of systems and conditions, some of which are presented in this paper.

scholarly journals Transient Enhanced Diffusion and Gettering of Dopants in Ion Implanted Silicon

1984 ◽  
Vol 36 ◽  
Author(s):  
S. J. Pennycook ◽  
J. Narayan ◽  
R. J. Culbertson
Keyword(s):  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Solid Phase ◽  
Subsequent Annealing ◽  
Dislocation Loops ◽  
Enhanced Diffusion ◽  
Transient Enhanced Diffusion ◽  
Dopant Profile ◽  
Dopant Atoms ◽  
Ion Implanted

ABSTRACTWe have studied in detail the transient enhanced diffusion observed during furnace or rapid-thermal-annealing of ion-implanted Si. We show that the effect originates in the trapping of Si atoms by dopant atoms during implantation, which are retained during solid-phase-epitaxial (SPE) growth but released by subsequent annealing to cause a transient dopant precipitation or profile broadening. The interstitials condense to form a band of dislocation loops located at the peak of the dopant profile, which may be distinct from the band formed at the original amorphous/crystalline interface. The band can develop into a network and effectively getter the dopant. We discuss the conditions under which the various effects may or may not be observed, and discuss preliminary observations on As+ implanted Si.

The Role of Vacancies and Interstitials in Transient Enhanced Diffusion of Arsenic Implanted into Silicon

1997 ◽  
Vol 469 ◽  
Author(s):  
D. Venables ◽  
V. Krishnamoorthy ◽  
H.- J. Gossmann ◽  
A. Lilak ◽  
K. S. Jones ◽  
...  
Keyword(s):  
Fermi Level ◽  
Point Defect ◽  
Boron Diffusion ◽  
Direct Role ◽  
Enhanced Diffusion ◽  
Projected Range ◽  
Transient Enhanced Diffusion ◽  
Diffusion Enhancement ◽  
Recombination Centers

ABSTRACTBoron and antimony doped superlattices (DSLs) were implanted with arsenic at 40 keV to doses of 2×1014 cm−2, 5×1015 cm−2 and 2×1016 cm−2. Increasing the arsenic dose above 5×1015 cm−2 resulted in a reduction in the extent of arsenic transient enhanced diffusion (TED) following annealing at 700°C, 16 hr. Concurrent with this reduction in TED was a reduction in the number of free interstitials beyond the end-of-range, as measured by the boron diffusion enhancement in the doped superlattices. No enhancement in antimony diffusivity was observed in this region, indicating that vacancies play no direct role in the diffusion of arsenic in this region, although an indirect role for vacancies as recombination centers for mobile interstitials is not precluded by these experiments. We conclude that interstitials dominate arsenic diffusion in the end-of-range region and beyond. Interpretation of the DSL data in the projected range region is complicated by Fermi level and segregation effects and no definitive conclusion can be reached about the point defect populations in this region.

Quantitation of Δ8-THC, Δ9-THC, Cannabidiol and 10 Other Cannabinoids and Metabolites in Oral Fluid by HPLC–MS-MS

2020 ◽  
Author(s):  
Lin Lin ◽  
Piyadarsha Amaratunga ◽  
Jerome Reed ◽  
Pornkamol Huang ◽  
Bridget Lorenz Lemberg ◽  
...  
Keyword(s):  
Human Subject ◽  
High Performance ◽  
Oral Fluid ◽  
Solid Phase ◽  
Forensic Toxicology ◽  
High Concentration ◽  
Driving Impairment ◽  
Three Samples ◽  
Cannabidiolic Acid ◽  
Liquid Chromatography Tandem Mass

Abstract Quantitative analysis of Δ9-tetrahydrocannabinol (Δ9-THC) in oral fluid has gained increasing interest in clinical and forensic toxicology laboratories. New medicinal and/or recreational cannabinoid products require laboratories to distinguish different patterns of cannabinoid use. This study validated a high-performance liquid chromatography-tandem mass spectrometry method for 13 different cannabinoids, including (-)-trans-Δ8-tetrahydrocannabinol (Δ8-THC), (-)-trans-Δ9-tetrahydrocannabinol (Δ9-THC), cannabidiol (CBD), Δ9-tetrahydrocannabinolic acid-A (Δ9-THCA-A), cannabidiolic acid (CBDA), 11-hydroxy-Δ9-tetrahydrocannabinol (11-OH-Δ9-THC), 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (Δ9-THCCOOH), tetrahydrocannabivarin (THCV), cannabidivarin (CBDV), cannabidiorcol (CBD-C1), cannabichromene (CBC), cannabinol (CBN) and cannabigerol (CBG), in oral fluid. Baseline separation was achieved in the entire quantitation range between Δ9-THC and its isomer Δ8-THC. The quantitation range of Δ9-THC, Δ8-THC and CBD was from 0.1 to 800 ng/mL. Two hundred human subject oral fluid samples were analyzed with this method after solid phase extraction. Among the 200 human subject oral fluid samples, all 13 cannabinoid analytes were confirmed in at least one sample. Δ8-THC was confirmed in 11 samples, with or without the presence of Δ9-THC. A high concentration of 11-OH-Δ9-THC or Δ9-THCCOOH (>400 ng/mL) was confirmed in three samples. CBD, Δ9-THCA-A, THCV, CBN and CBG were confirmed in 74, 39, 44, 107 and 112 of the 179 confirmed Δ9-THC-positive samples, respectively. The quantitation of multiple cannabinoids and metabolites in oral fluid simultaneously provides valuable information for revealing cannabinoid consumption and interpreting cannabinoid-induced driving impairment.

scholarly journals A Study of the Impact of Graphite on the Kinetics of SPS in Nano- and Submicron WC-10%Co Powder Compositions

Ceramics ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 331-363
Author(s):  
Eugeniy Lantcev ◽  
Aleksey Nokhrin ◽  
Nataliya Malekhonova ◽  
Maksim Boldin ◽  
Vladimir Chuvil'deev ◽  
...  
Keyword(s):  
Activation Energy ◽  
Solid Phase ◽  
Continuous Heating ◽  
Diffusion Creep ◽  
Hard Alloys ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
The Impact ◽  
Kinetics Of

This study investigates the impact of carbon on the kinetics of the spark plasma sintering (SPS) of nano- and submicron powders WC-10wt.%Co. Carbon, in the form of graphite, was introduced into powders by mixing. The activation energy of solid-phase sintering was determined for the conditions of isothermal and continuous heating. It has been demonstrated that increasing the carbon content leads to a decrease in the fraction of η-phase particles and a shift of the shrinkage curve towards lower heating temperatures. It has been established that increasing the graphite content in nano- and submicron powders has no significant effect on the SPS activation energy for “mid-range” heating temperatures, QS(I). The value of QS(I) is close to the activation energy of grain-boundary diffusion in cobalt. It has been demonstrated that increasing the content of graphite leads to a significant decrease in the SPS activation energy, QS(II), for “higher-range” heating temperatures due to lower concentration of tungsten atoms in cobalt-based γ-phase. It has been established that the sintering kinetics of fine-grained WC-Co hard alloys is limited by the intensity of diffusion creep of cobalt (Coble creep).

Sign in / Sign up

Export Citation Format

Share Document