Impurity Diffusion During RTA

1984 ◽  
Vol 35 ◽  
Author(s):  
R.B. Fair
Keyword(s):  
Anomalous Diffusion ◽  
Solubility Enhancement ◽  
Impurity Diffusion ◽  
High Dose ◽  
Dopant Diffusion ◽  
Enhanced Diffusion ◽  
Intrinsic Diffusivity ◽  
Physical Phenomena ◽  
Induced Dislocation ◽  
Dislocation Formation

ABSTRACTEnhanced dopant diffusion during RTA depends upon whether the following physical phenomena occur individually or in combination: (1) amorphization of the Si, (2) damage-induced dislocation formation, (3) damage annealing, (4) self-interstitial trapping, (5) solubility enhancement. RTA of B in crystalline or preamorphized Si presents significantly different environments for enhanced diffusion. In preamorphized Si, enhanced B diffusion is modeled as increased B solubility following SPE. In addition, a different intrinsic diffusivity is observed which corresponds to B diffusion in preamorphized Si. Anomalous diffusion of B and As from high dose implants can be modeled with the same mechanism -- self-interstitial trapping following SPE.

scholarly journals Self- and Dopant Diffusion in Extrinsic Boron Doped Isotopically Controlled Silicon Multilayer Structures

2002 ◽  
Vol 719 ◽  
Author(s):  
Ian D. Sharp ◽  
Hartmut A. Bracht ◽  
Hughes H. Silvestri ◽  
Samuel P. Nicols ◽  
Jeffrey W. Beeman ◽  
...  
Keyword(s):  
Multilayer Structure ◽  
Secondary Ion Mass Spectrometry ◽  
Diffusion Processes ◽  
Quantitative Description ◽  
Multilayer Structures ◽  
Dopant Diffusion ◽  
Enhanced Diffusion ◽  
Self Diffusion ◽  
Boron Doped ◽  
P Type

AbstractIsotopically controlled silicon multilayer structures were used to measure the enhancement of self- and dopant diffusion in extrinsic boron doped silicon. 30Si was used as a tracer through a multilayer structure of alternating natural Si and enriched 28Si layers. Low energy, high resolution secondary ion mass spectrometry (SIMS) allowed for simultaneous measurement of self- and dopant diffusion profiles of samples annealed at temperatures between 850°C and 1100°C. A specially designed ion-implanted amorphous Si surface layer was used as a dopant source to suppress excess defects in the multilayer structure, thereby eliminating transient enhanced diffusion (TED) behavior. Self- and dopant diffusion coefficients, diffusion mechanisms, and native defect charge states were determined from computer-aided modeling, based on differential equations describing the diffusion processes. We present a quantitative description of B diffusion enhanced self-diffusion in silicon and conclude that the diffusion of both B and Si is mainly mediated by neutral and singly positively charged self-interstitials under p-type doping. No significant contribution of vacancies to either B or Si diffusion is observed.

Effect of Energy and Dose on Transient-Enhanced Diffusion and Defect Microstructure in Low Energy High Dose As+ Implanted Si

1996 ◽  
Vol 438 ◽  
Author(s):  
V. Krishnamoorthy ◽  
D. Venables ◽  
K. Moeller ◽  
K. S. Jones ◽  
B. Freer
Keyword(s):  
Point Defects ◽  
Surface Recombination ◽  
High Dose ◽  
Enhanced Diffusion ◽  
Projected Range ◽  
Diffusion Enhancement ◽  
Defect Microstructures ◽  
Dose Dependent ◽  
Higher Doses ◽  
Defect Microstructure

Abstract(001) CZ silicon wafers were implanted with arsenic (As+) at energies of 10–50keV to doses of 2×1014 to 5×1015/cm2. All implants were amorphizing in nature. The samples were annealed at 700°C for 16hrs. The resultant defect microstructures were analyzed by XTEM and PTEM and the As profiles were analyzed by SIMS. The As profiles showed significantly enhanced diffusion in all of the annealed specimens. The diffusion enhancement was both energy and dose dependent. The lowest dose implant/annealed samples did not show As clustering which translated to a lack of defects at the projected range. At higher doses, however, projected range defects were clearly observed, presumably due to interstitials generated during As clustering. The extent of enhancement in diffusion and its relation to the defect microstructure is explained by a combination of factors including surface recombination of point defects, As precipitation, As clustering and end of range damage.

Simulation of Transient Enhanced Diffusion in Silicon Taking into Account Ostwald Ripening of Defects

2002 ◽  
Vol 717 ◽  
Author(s):  
Masashi Uematsu
Keyword(s):  
Time Dependence ◽  
Diffusion Model ◽  
Low Dose ◽  
Ostwald Ripening ◽  
High Dose ◽  
Enhanced Diffusion ◽  
Annealing Conditions ◽  
Transient Enhanced Diffusion ◽  
High Dose Implantation ◽  
Medium Dose

AbstractThe transient enhanced diffusion (TED) of high-dose implanted P is simulated taking into account Ostwald ripening of end-of-range (EOR) defects. First, we integrated a basic diffusion model based on the simulation of in-diffusion, where no implanted damages are involved. Second, from low-dose implantation, we developed a model for TED due to {311} self-interstitial (I) clusters involving Ostwald ripening and the dissolution of {311} clusters. Third, from medium-dose implantation, we showed that P-I clusters should be taken into account, and during the diffusion, the clusters are dissolved to emit self-interstitials that also contribute to TED. Finally, from high-dose implantation, EOR defects are modeled and we derived a formula to describe the time-dependence for Ostwald ripening of EOR defects, which is more significant at higher temperatures and longer annealing times. The simulation satisfactorily predicts the TED for annealing conditions, where the calculations overestimate the diffusion without taking Ostwald ripening into account.

Effect of Energy and Dose on Transient-Enhanced Diffusion and Defect Microstructure in Low Energy High Dose As+ Implanted Si

1996 ◽  
Vol 439 ◽  
Author(s):  
V. Krishnamoorthy ◽  
D. Venables ◽  
K. Moeller ◽  
K. S. Jones ◽  
B. Freer
Keyword(s):  
Point Defects ◽  
Surface Recombination ◽  
High Dose ◽  
Enhanced Diffusion ◽  
Projected Range ◽  
Diffusion Enhancement ◽  
Defect Microstructures ◽  
Dose Dependent ◽  
Higher Doses ◽  
Defect Microstructure

Abstract(001) CZ silicon wafers were implanted with arsenic (As+) at energies of 10–50keV to doses of 2x 1014 to 5x1015/cm2. All implants were amorphizing in nature. The samples were annealed at 700°C for 16hrs. The resultant defect microstructures were analyzed by XTEM and PTEM and the As profiles were analyzed by SIMS. The As profiles showed significantly enhanced diffusion in all of the annealed specimens. The diffusion enhancement was both energy and dose dependent. The lowest dose implant/annealed samples did not show As clustering which translated to a lack of defects at the projected range. At higher doses, however, projected range defects were clearly observed, presumably due to interstitials generated during As clustering. The extent of enhancement in diffusion and its relation to the defect microstructure is explained by a combination of factors including surface recombination of point defects, As precipitation, As clustering and end of range damage.

Analysis of a Model for Anomalous-Diffusion Behavior of CO2 in the Macromolecular-Network Structure of Coal

SPE Journal ◽  
2010 ◽  
Vol 16 (04) ◽  
pp. 856-863 ◽  
Author(s):  
Saikat Mazumder ◽  
Fred Vermolen ◽  
Johannes Bruining
Keyword(s):  
Anomalous Diffusion ◽  
Intermediate Phase ◽  
Time Behavior ◽  
Enhanced Diffusion ◽  
Coal Swelling ◽  
Pure Diffusion ◽  
Macromolecular Network ◽  
Diffusion In Polymers ◽  
Saturation Effects ◽  
Stress Induced Diffusion

Summary This paper gives an analysis of the Thomas and Windle model (Thomas and Windle 1982) to determine its usefulness for describing anomalous diffusion of CO2 in coal and its relation to matrix swelling. In addition, a finite-element description for this model is derived. For reasons of easy reference, a shortened derivation of the Thomas and Windle model is presented, which was originally derived to describe diffusion in polymers. The derivation includes the surface saturation effects proposed by Hui et al. (1987a, 1987b). Because the cumulative sorption showed tα behavior with α > 0.5, the behavior was described as enhanced diffusion or even superdiffusion. Analysis of the model equation shows no evidence for superdiffusion even if non-Fickian behavior is observed [i.e., there is (1) an initial phase in which the coal surface gets saturated with a slope > 0.5 in a log-log plot of cumulative sorption vs. time, (2) an intermediate phase that shows the typical square-root-of-time behavior of an ordinary diffusion process, and (3) a final phase with a slope < 0.5 toward equilibrium]. The cumulative mass is for all times less than what would have been obtained for pure diffusion in a particle characterized by a rubber diffusion coefficient. The slow saturation at the surface masks a process where fast stress-induced diffusion dominates, which indeed can be faster than Fickian. The cumulative sorption rates give behavior similar to the Rückenstein model (Rückenstein et al. 1971), but the advantage of the Thomas and Windle model is that it can also calculate the resulting coal-swelling effects.

Unsupervised learning of anomalous diffusion data an anomaly detection approach

2021 ◽  
Author(s):  
Gorka Muñoz-Gil ◽  
Guillem Guigo i Corominas ◽  
Maciej Lewenstein
Keyword(s):  
Anomalous Diffusion ◽  
Diffusion Processes ◽  
Theoretical Models ◽  
Diffusion Models ◽  
Supervised Machine Learning ◽  
Machine Learning Techniques ◽  
Physical Parameters ◽  
Diffusion Data ◽  
Detection Approach ◽  
Physical Phenomena

Abstract The characterization of diffusion processes is a keystone in our understanding of a variety of physical phenomena. Many of these deviate from Brownian motion, giving rise to anomalous diffusion. Various theoretical models exists nowadays to describe such processes, but their application to experimental setups is often challenging, due to the stochastic nature of the phenomena and the difficulty to harness reliable data. The latter often consists on short and noisy trajectories, which are hard to characterize with usual statistical approaches. In recent years, we have witnessed an impressive effort to bridge theory and experiments by means of supervised machine learning techniques, with astonishing results. In this work, we explore the use of unsupervised methods in anomalous diffusion data. We show that the main diffusion characteristics can be learnt without the need of any labelling of the data. We use such method to discriminate between anomalous diffusion models and extract their physical parameters. Moreover, we explore the feasibility of finding novel types of diffusion, in this case represented by compositions of existing diffusion models. At last, we showcase the use of the method in experimental data and demonstrate its advantages for cases where supervised learning is not applicable.

Prediction of High Dose Ion Implantation Profiles as Influenced by Radiation Induced Transport and Sputtering

1985 ◽  
Vol 45 ◽  
Author(s):  
M. Rangaswamy ◽  
D. Farkas
Keyword(s):  
Probability Distributions ◽  
Practical Interest ◽  
High Dose ◽  
High Fluence ◽  
Enhanced Diffusion ◽  
Preferential Sputtering ◽  
Radiation Enhanced Diffusion ◽  
Defect Probability ◽  
Radiation Induced ◽  
Effects Of Radiation

ABSTRACTVarious models for predicting high fluence ion collection profiles are reviewed. Recent calculations based on the diffusion approximation are described. The solute and defect probability distributions are calculated by a MONTECARLO code, TRIM. The method takes into account the effects of sputtering, including preferential sputtering of one of the components, and lattice dilation. In addition, the effects of radiation enhanced diffusion and radiation induced segregation are also considered. The calculations include the coupling of solute and defect fluxes. The described formalism can account for observed maximum attainable concentrations and distributions in high fluence implantation conditions of practical interest.

Transient enhanced diffusion and defect microstructure in high dose, low energy As+ implanted Si

1998 ◽  
Vol 84 (11) ◽  
pp. 5997-6002 ◽  
Author(s):  
V. Krishnamoorthy ◽  
K. Moller ◽  
K. S. Jones ◽  
D. Venables ◽  
J. Jackson ◽  
...  
Keyword(s):  
Low Energy ◽  
High Dose ◽  
Enhanced Diffusion ◽  
Transient Enhanced Diffusion ◽  
Defect Microstructure

Boron Enhanced Diffusion Due to High Energy Ion-Implantation and Its Suppression by Using RTA Process

1994 ◽  
Vol 354 ◽  
Author(s):  
Atsuki ONO ◽  
Hitoshi ABIKO ◽  
Isarai SAKAI
Keyword(s):  
Anomalous Diffusion ◽  
High Energy ◽  
Device Fabrication ◽  
Systematic Analysis ◽  
Enhanced Diffusion ◽  
Transient Enhanced Diffusion ◽  
Dopant Profile ◽  
Initial Stage ◽  
Boron Implantation ◽  
Shallow Channel

AbstractSIMS measurements revealed that high energy boron-implantation causes transient enhanced diffusion (TED) of a shallow dopant profile due to Si interstitials even for a relatively low dose of ∼2E13cm-2. By systematic analysis, it is found that this anomalous diffusion is most significant in 700∼800°C annealing, and it takes place in the initial stage (less than 30sec for 800°C) of annealing. Moreover, this anomalous diffusion is more considerable than the enhanced diffusion during oxidation (OED) in practical device fabrication processes. It is found that rapid thermal annealing (RTA) at 1000-1100°C is effective for suppressing the transient enhanced diffusion and realizing a shallow channel profile for deep sub-micron devices.

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