Ostwald Ripening of {113} Defects Precursors and Transient Enhanced Diffusion

1999 ◽  
Vol 568 ◽  
Author(s):  
Giovanni Manninoo ◽  
Nicholas E.B. Cowem ◽  
Peter A. Stolk ◽  
Fred Roozeboom ◽  
Hendrik G.A. Huizing ◽  
...  
Keyword(s):  
Point Defects ◽  
Ostwald Ripening ◽  
Ion Beam ◽  
Extended Defects ◽  
Defect Band ◽  
Enhanced Diffusion ◽  
Dissociation Energies ◽  
Marker Layer ◽  
High Supersaturation ◽  
Very High

ABSTRACTThe ripening of ion-beam generated point defects into extended defects has been investigated in detail. The interstitial supersaturation has been extracted from boron marker-layer diffusion after annealing under non-equilibrium defect conditions. We measured a very high initial supersaturation followed by a decrease over many orders of magnitude with a characteristic “plateau” related to the presence of {113} defects. A continuum inverse model has been used to properly describe the ripening of point defects into clusters and their evolution in the presence of a remote sink, e.g. the surface. It evidences that a nonconservative Ostwald ripening process takes place inside the defect band during the annealing and sustains the interstitial supersaturation. The model reveals moreover an oscillatory behaviour of dissociation energies of the nanometer-sized defects which are responsible for the initial high supersaturation. These defects are believed to be {113} precursors.

Effect of Extended Defects on the Enhanced Diffusion of Phosphorus Implanted Silicon

1999 ◽  
Vol 568 ◽  
Author(s):  
P. H. Keys ◽  
J. H. Li ◽  
E. Heitman ◽  
P. A. Packan ◽  
M. E. Law ◽  
...  
Keyword(s):  
Species Interactions ◽  
Secondary Ion Mass Spectrometry ◽  
Ion Beam ◽  
Effective Diffusion ◽  
Chemical Species ◽  
High Dose ◽  
Extended Defects ◽  
Near Surface ◽  
Enhanced Diffusion ◽  
Marker Layer

ABSTRACTExtended defects resulting from ion implantation are believed to act in some cases as a driving force behind transient enhanced diffusion (TED). We use secondary ion mass spectrometry (SIMS) to study the diffusion enhancements of an underlying boron doped spike after creating implant damage in the near surface region. Diffusion enhancements are compared for silicon implants and phosphorus implants to distinguish between factors related to chemical species interactions versus those related to ion beam damage. Transmission electron microscopy (TEM) is used to investigate the existence and dissolution of extended defects. {311} extended defects are clearly visible in self-implanted samples but absent in phosphorus doped samples. The extended defects resulting from phosphorus implantation are small (20Å to 60Å diameter) “dot” defects barely resolvable by conventional TEM. methods. Despite the marked differences in defect morphology, diffusion enhancements in the boron marker layer are observable for both species. Results comparing the TED of a buried marker layer after P+ and Si+ show a larger overall effective diffusion length results after high dose (1x1014 cm−2) phosphorus implants. Visible defects in phosphorus implanted silicon are not the only source of TED, suggesting the existence of sub-microscopic phosphorus interstitial clusters (PIC). This provides important insight into the affect of phosphorus on TED.

Point and Extended Defect Interactions in Silicon

1997 ◽  
Vol 469 ◽  
Author(s):  
M. E. Law ◽  
S. K. Earles
Keyword(s):  
Point Defects ◽  
Quantitative Model ◽  
Extended Defects ◽  
Form Complex ◽  
Extended Defect ◽  
Enhanced Diffusion ◽  
Defect Interactions ◽  
Short Time ◽  
Surface Sink

ABSTRACTTransient Enhanced Diffusion (TED) is one of the biggest modeling challenges present in predicting scaled technologies. Damage from implantation of dopant ions changes the diffusivities of the dopants and precipitates to form complex extended defects. Developing a quantitative model for the defect behavior during short time, low temperature anneals is a key to explaining TED. The surface can play a defining role in the removal of point defects from the bulk, but there is a lot of controversy over the role and strength of the surface sink for point defects. The controversy will be reviewed, and new experimental results will be presented that investigate the role of the surface on TED.

Modeling of Dopant Diffusion during Annealing of Sub-Amorphizing Implants

1993 ◽  
Vol 316 ◽  
Author(s):  
Scott Dunham
Keyword(s):  
Point Defects ◽  
Model Development ◽  
Three Dimensional ◽  
Fabrication Process ◽  
Physical Models ◽  
Extended Defects ◽  
Enhanced Diffusion ◽  
Complicated Process ◽  
Parameter Values ◽  
Multiple Interactions

Ion implant annealing is a complicated process involving the interactions of point defects generated during the implantation, implanted or previously present dopants, and extended defects which form as a result of the implant damage. To effectively model the process, it is essential to determine the critical processes, assess the validity of assumptions and calculate appropriate parameter values. In addition, implant annealing is just one element in the VLSI fabrication process, and the model development must consider the process as part of the broad range of experimental observations, as it is only through consistent physical models that simulators can predict the multiple interactions and two and three-dimensional effects present in VLSI structures. This work focuses on enhanced diffusion following silicon implants below the amorphization threshold as a function of dose, energy and time.

Irradiation-Enhanced Diffusion in Metallic Glasses

1998 ◽  
Vol 540 ◽  
Author(s):  
T. Schuler ◽  
P. Scharwaechter ◽  
W.F.J. Frank
Keyword(s):  
Point Defects ◽  
Metallic Glasses ◽  
Ion Beam ◽  
Ion Beam Sputtering ◽  
Radiotracer Technique ◽  
Enhanced Diffusion ◽  
Self Diffusion ◽  
Beam Sputtering ◽  
Diffusion Mechanisms ◽  
Dynamics Simulations

AbstractThe influence of irradiation with particles (H+, He+, 15N+) on the self-diffusion in relaxed metallic glasses (59Fe in Fe91Zr9, 59Fe in Co58Fe5Ni10Si11B16, 95Zr in Fe24Zr76) has been investigated by means of the radiotracer technique using ion-beam sputtering for serial sectioning of the specimens. Combination of the results of these experiments with accompanying molecular-dynamics simulations not only leads to an understanding of a novel phenomenon of irradiation-enhanced diffusion observed on these materials, but also confirms and refines our previous view that, in the absence of irradiation, diffusion in relaxed metallic glasses occurs by collective diffusion mechanisms not involving intrinsic point defects as diffusion vehicles.

Defects and Diffusion in Silicon: An Overview

1999 ◽  
Vol 568 ◽  
Author(s):  
N.E.B. Cowern ◽  
G. Mannino ◽  
P.A. Stolk ◽  
M.J.J. Theunissen
Keyword(s):  
Point Defects ◽  
Technology Development ◽  
Silicon Crystal ◽  
Atomic Scale ◽  
Extended Defects ◽  
High Concentration ◽  
Concentration Gradients ◽  
Enhanced Diffusion ◽  
Impurity Atoms ◽  
And Diffusion

ABSTRACTAt the current pace of semiconductor technology development, transistor dimensions in advanced IC products will approach the range of a few tens of nanometers within the next decade. This presents a major challenge for our understanding of defects and diffusion in these tiny devices during processing. In response, an almost explosive growth in research on process physics has taken place at universities, national institutes and industry research labs worldwide. The central issue is the phenomenon of nonequilibrium diffusion driven by processing steps such as oxide growth, high concentration gradients of impurities, and annealing of damage caused by ion implantation. Nonequilibrium diffusion arises from perturbations to the natural thermal equilibrium concentrations of point defects - interstitial atoms and vacancies - in the silicon crystal. This paper gives a snapshot of our current understanding of the atomic-scale interactions between point defects and impurity atoms, extended defects and interfaces, as revealed by recent experimental and theoretical studies. The paper emphasizes the important role played by defect cluster ripening during transient enhanced diffusion and dopant activation.

The Roles of Energetic Displacement Cascades in Ion Beam Modifications of Materials

1986 ◽  
Vol 74 ◽  
Author(s):  
R. S. Averback ◽  
S. -J. Kim ◽  
T. Diaz de la Rubia
Keyword(s):  
Point Defects ◽  
Elevated Temperatures ◽  
Ion Beam ◽  
Experimental Studies ◽  
Structural Disorder ◽  
Microstructural Development ◽  
Enhanced Diffusion ◽  
Displacement Cascades ◽  
Radiation Enhanced Diffusion ◽  
Cascade Processes

AbstractThe roles of energetic displacement cascades are ubiquitous in the fields of radiation damage and ion beam modifications of materials. These roles can be described on two time scales. For the first, which lasts ≈ 10-11 s, small cascade volumes are characterized by large supersaturations of point defects, structural disorder, and energy densities in excess of some tenths of eV's per atom. During this period, the system can be driven far from equilibrium with significant rearrangement of target atoms and the production of Frenkel pairs. Experimental studies of ion beam mixing in conjunction with molecular dynamics computer simulations, have contributed largely toward understanding these dynamic cascade processes. At later times, the microstructure of the material evolves as cascades begin to overlap, or at elevated temperatures, point defects migrate away from their nascent cascades. It will be shown how the primary state of damage in cascades influences this microstructural development. Examples involving radiation-enhanced diffusion and ion-induced amorphization will be discussed.

Microstructural Evolution in Reduced TiO2

1981 ◽  
Vol 39 ◽  
pp. 74-75
Author(s):  
W. T. Donlon ◽  
S. Shinozaki ◽  
E. M. Logothetis ◽  
W. Kaizer
Keyword(s):  
Microstructural Evolution ◽  
Point Defects ◽  
Extended Defects ◽  
Small Deviations ◽  
Controlled Atmospheres ◽  
Limited Solubility ◽  
Thin Foils ◽  
Heat Treated ◽  
Porous Polycrystalline ◽  
Crystallographic Shear

Since point defects have a limited solubility in the rutile (TiO2) lattice, small deviations from stoichiometry are known to produce crystallographic shear (CS) planes which accomodate local variations in composition. The material used in this study was porous polycrystalline TiO2 (60% dense), in the form of 3mm. diameter disks, 1mm thick. Samples were mechanically polished, ion-milled by conventional techniques, and initially examined with the use of a Siemens EM102. The electron transparent thin foils were then heat-treated under controlled atmospheres of CO/CO2 and H2 and reexamined in the same manner.The “as-received” material contained mostly TiO2 grains (∼5μm diameter) which had no extended defects. Several grains however, aid exhibit a structure similar to micro-twinned grains observed in reduced rutile. Lattice fringe images (Fig. 1) of these grains reveal that the adjoining layers are not simply twin related variants of a single TinO2n-1 compound. Rather these layers (100 - 250 Å wide) are alternately comprised of stoichiometric TiO2 (rutile) and reduced TiO2 in the form of Ti8O15, with the Ti8O15 layers on either side of the TiO2 being twin related.

Ion Beam Mixing of Ni-Ti Bilayered Thin Films

1985 ◽  
Vol 43 ◽  
pp. 290-291
Author(s):  
A. K. Rai ◽  
R. S. Bhattacharya ◽  
M. H. Rashid
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Amorphous Alloys ◽  
Ion Beam ◽  
Ion Bombardment ◽  
High Energy ◽  
Mixing Efficiency ◽  
Ion Beam Mixing ◽  
Enhanced Diffusion ◽  
Binary Metal

Ion beam mixing has recently been found to be an effective method of producing amorphous alloys in the binary metal systems where the two original constituent metals are of different crystal structure. The mechanism of ion beam mixing are not well understood yet. Several mechanisms have been proposed to account for the observed mixing phenomena. The first mechanism is enhanced diffusion due to defects created by the incoming ions. Second is the cascade mixing mechanism for which the kinematicel collisional models exist in the literature. Third mechanism is thermal spikes. In the present work we have studied the mixing efficiency and ion beam induced amorphisation of Ni-Ti system under high energy ion bombardment and the results are compared with collisional models. We have employed plan and x-sectional veiw TEM and RBS techniques in the present work.

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.

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