bluuebunny/crossref_metadata_2025 huggingface dataset:
Energetic Landscapes and Diffusion Properties in FeCu Alloys
Authors: Soisson Frederic , Fu Chu Chun
Published: March 2009

The thermodynamic and kinetic properties of Fe-Cu alloys are studied by ab initio
calculations, in the framework of a multiscale modeling of precipitation kinetics. The configuration
energies at various compositions, the solute migration and binding energies, as well as the vacancy
formation and binding energies are computed. The effects of the local copper distribution on the
migration barriers are considered. We show that a simple diffusion model with effective interactions
on a rigid lattice, which includes a description of the saddle-point configurations, captures the main
features of the energetic landscapes explored by the vacancy during its diffusion in dilute and
concentrated configurations.
Cluster Dynamics Modeling of Materials: Advantages and Limitations
Authors: Barbu Alain , Clouet Emmanuel
Published: March 2009

The aim of this paper is to give a short review on cluster dynamics modeling in the field
of atoms and point defects clustering in materials. It is shown that this method, due to its low
computer cost, can handle long term evolution that cannot, in many cases, be obtained by Lattice
Kinetic Monte Carlo methods. Indeed, such a possibility is achieved thanks to an important
drawback that is the loss of space correlations of the elements of the microstructures. Some
examples, in the field of precipitation and irradiation of metallic materials are given. The limitations
and difficulties of this method are also discussed. Unsurprisingly, it is shown that it goes in a very
satisfactory way when the objects are distributed homogeneously. Conversely, the source term
describing the primary damage under irradiation, by nature heterogeneous in space and time, is
tricky to introduce especially when displacement cascades are produced.
Anisotropy of the Vacancy Migration in Ti, Zr and Hf Hexagonal Close-Packed Metals from First Principles
Authors: Vérité Guillaume , Willaime F. , Fu Chu Chun
Published: March 2009

The vacancy properties in group-IV hexagonal close-packed metals (Ti, Zr and
Hf) have been investigated by Density Functional Theory (DFT) calculations performed with
the SIESTA code. The migration energies are found to be systematically lower by »0.15 eV
within the basal plane than out of the basal plane. The electronic origin of this significant
contribution to diffusion anisotropy is evidenced by the analysis of the local electronic densities
of states and by a comparison with and empirical potential. The average value of the migra-
tion energy is in very good agreement with available experimental data in Zr. The activation
energies for self-diffusion obtained assuming a vacancy mechanism are in good agreement with
experiments in Zr and Hf, although slightly too small, but a significant discrepancy is observed
in Ti.
Inorganic Structure Prediction: Too much and not Enough
Authors: Le Bail Armel
Published: March 2009

Elementary to sophisticated approaches allow for crystal structure prediction from empirical and theoretical principles since a few decades. Some recent efforts in inorganic chemistry for the production and classification of structure-candidates are described. The discussion is focused on an incredibly huge list of hypothetical zeolites, more modest series of aluminum fluoride polymorphs, or titanosilicates (etc) build up from the exploration of a special topological class, the N-connected 3D frameworks.
Refinement of the Cu Structure by Oscillatory Compression Test
Authors: Rodak Kinga , Goryczka Tomasz
Published: March 2009

Polycrystalline Cu has been deformed at room temperature by oscillatory compression method to true reduction εh = 0.6 and 1. Microstructure by using transmission electron microscopy (TEM) and texture evolution after deformations was investigated. Oscillatory compressed microareas contains two distinctive regions: fine grains inside banded microstructure with large misorientation and surrounding matrix with submicrometer subgrains with a fraction of both low and high angle boundaries. Moreover nucleation of new grains under recrystallization takes place at the local-regions. The study of the crystal orientation distribution during applied deformation showed that the pole figure registered for the sample after compression shows ring of pole density, which concentrates around projection of <011>. Oscillatory compression causes formation of two axial texture components: <001> and <011>.
Influence of the Ga Alloying on the Properties of NiAl Based Alloys
Authors: Koval Yuri N. , Monastyrsky G.E. , Odnosum Valeri V. , Czeppe Tomasz , Musienko R.Ya. , Sezonenko A.Yu.
Published: March 2009

Influence of the Ga alloying on the crystal structure and parameters of the martensitic transformation are presented. X-ray diffraction has shown the multiphase composition of the samples (β (B2)- phase, γ′ (L12)-phase, (L10)-martensitic phase, Ni5Al3-phase). Metallographic investigations have demonstrated the coarse grain of B2 phase with non-regular needles of Ni3Al and typical martensitic structure. Ga did not suppress the martensitic transformation in NiAlGa alloys. The Ni to Al ratio and quantity of Ga determine the parameters of martensitic transformation.
Preparation by Twin Roll Casting and Characterization of TiNi Shape Memory Alloys Strips
Authors: Portier Richard , Vermaut Philippe , Ochin Patrick , Goryczka Tomasz , Malarría Jorge
Published: March 2009

The thermoelastic martensitic transformation which gives remarkable functional properties to Shape Memory Alloys (SMA) is very sensitive to the chemistry of the alloys and to its microstructure. In many cases, especially for alloys with high transformation temperatures, applications are limited by the poor ductility. To overcome the brittleness of SMA, one approach can be effective : the development of non conventional production technologies which enable to obtain materials in forms close to requirements: strips of SMA have been prepared by Twin Roll Casting (TRC). The formation of a solid sheet with plane surface is only possible for a limited combination of the different machine parameters and they will be discussed. For comprehension of the process parameters effect, the attention will be focused on TiNi. Microstructures and functional properties will be examined in relation with the microstructures induced by the technique or after specific thermal treatment.
Effect of L21 Ordering on the Martensitic and Intermartensitic Transformations in a Ni-Mn-Ga Shape Memory Alloy
Authors: Seguí Concepcio , Pons Jaume , Cesari Eduard
Published: March 2009

The present work analyses the influence of austenite ordering on a single crystal Ni-Mn- Ga alloy which displays, on cooling, a sequence of martensitic (MT) and intermartensitic (IMT) transformations. The MT and IMT show distinct behaviour after ageing in austenite: while the MT temperatures are not affected by the performed heat treatments, the IMT shifts toward lower temperatures after quenching from increasing temperatures, progressive recovery occurring upon ageing in parent phase. Such evolution can be related to changes in the L21 order degree, in the sense that ordering favours the occurrence of the intermartensitic transformation, while it does not affect noticeably the forward and reverse martensitic transformation temperatures. The closeness of the free energies of the different martensite structures allows to explain this behaviour.
The Effect of the Annealing Parameters on the Structure and Characteristic Temperatures of the Nonstoichiometric Ni2MnGa Alloys
Authors: Gigla Marek , Szczeszek Paweł
Published: March 2009

Transmission electron microscopy studies of the Ni2MnGa alloy showed that in the diffraction patterns
there exist two additional effect apart from the spots given by the parent L21 Heusler phase and the
tetragonal no modulate martensite. The first effect was the presence of sharp extra spots, lying on a
direction significantly deviated from the <110>* for [001]β zone axis. These spots are connected with
modulation of the parent phase. The value of the deviation angle is about 11-12°. The detailed analysis
showed that the direction of the propagation vector of modulation is <641> type direction. The second
effect visible in the [001]β diffraction patterns is the presence of the arcs located between the 220 type
parent phase spots.. The analysis of this objects suggests that some chemical modulation exists with the
period of <550>β. In this case short range ordering plays the essential role.
Characterization of Nitrided/Oxidized Layers Covering Ni-Ti Shape Memory Alloy
Authors: Goryczka Tomasz , Pączkowski Paweł , Lelątko Józef , Wierzchoń Tadeusz , Morawiec Henryk
Published: March 2009

In order to increase corrosion resistance, the NiTi shape memory alloy was covered by
protection layers using glow discharge method. Samples were nitrided with some oxygen addition at
temperatures: 350, 380, 400 and 800°C. Microstructure and sequence of obtained layers were
studied applying X-ray diffraction technique as well as electron microscopy. Low temperature
process produces a layers which consist of Ti3O5, TiN and Ni2Ti4O. Intermediate Ni3Ti layer was
between Ni2Ti4O and NiTi matrix. High temperature process forms TiO2 and TiN with interlayer
Ti2Ni. Surface does not contain phase with Ni, which is considered as toxic element.
The Influence of Aluminium Addition on the Microstructure of Zinc Pack Coatings
Authors: Michos N. , Chaliampalias D. , Vourlias G. , Pistofidis N. , Stergioudis F.
Published: March 2009

This work aims to investigate the feasibility of Zn-Al deposition on low alloy steels at temperatures from 400 up to 440oC by pack cementation process aiming to increase their corrosion resistance. A series of experiments were undertaken to investigate the effects of pack powder composition and the deposition temperature of the process. It was observed that the parameters of zinc content and temperature affect only the coating deposition speed, but not the phase composition of the as produced coating. Al forms an overlying layer that seals the zinc coating. In any case, the deposition of successive layers of Zn and Al is feasible with pack cementation. The corrosion performance of Zn-Al coatings formed with alternative methods is already studied and proved to be resistant in harsh environments. So the herein studied coatings are expected to be corrosion resistant. Furthermore as Al is much more resistive than Zn, these coatings are more effective than pure Zn ones.
Long Range Ordering in Spin Crossover Compounds
Authors: Kusz Joachim
Published: March 2009

The mechanism of the long range ordering during the spin crossover transition in the Fe (II) complexes is described in the paper.
Thickness Measurement of Thin Textured Films by a Novel X-Ray Diffraction Method Accounting for Secondary Extinction
Authors: Tomov I. , Vassilev S.
Published: March 2009

Accounting for secondary extinction (SE) of the intensities measured from a textured film
by means of conventional X-ray diffractometer, a new X-ray diffraction method is described for
determination of film thickness. Physically, the problem is restricted to using a reflection pair
corresponding to the main component of the texture. As model sample a vacuum-deposited silver
thin film is used.
Non-Destructive Quantitative Phase and Residual Stress Analysis Versus Depth Using Grazing X-Ray Diffraction
Authors: Skrzypek S.J. , Goły M. , Ratuszek Wiktoria , Kowalski Mieczyslaw
Published: March 2009

The non-destructive structure characterisation of surface layers for various kinds of ball bearings can be a powerful method in surface characterization and in quality control. The ball bearings were made of 100Cr6 steel and they were superfinished and mechanically burnished. An application of classical X-ray diffraction sin2ψ method and classical Bragg-Brentano diffraction geometry in these kinds of surface examinations make some problems in term of X-ray real depth of penetration. An application of methods based on grazing angle X-ray diffraction geometry, made possible to get real value of residual macro-stresses, retained austenite and additionally could be suitable in estimation of their gradient-like distribution versus depth under surface. An application of this geometry to X-ray diffraction phase analysis enabled to get phase contents versus thickness under surface in non-destructive way as well. The results are not infected by gradient-like distribution. The X-ray quantitative phase analysis was used to establish volume fraction of transformed retained austenite. Theoretical calculation of residual macro-stresses due to volume fraction of transformed austenite in ball bearings and following measurements of residual stresses were curried out as well. The mechanical burnishing of ball bearings caused big compressive residual stresses about – 1000 MPa and phase transformation of austenite in thin surface layer. These factors can influence on properties of following exploitation and durability.
X-Ray Diffraction and Electric Measurements of Phase Transformation in Li-Mn Spinels
Authors: Pielaszek J. , Dygas J.R. , Krok F. , Lisovytskiy D. , Kopeć Monika , Marzantowicz M.
Published: March 2009

Laboratory prepared and commercial Li-Mn spinels were studied. Making use of the
dedicated XRD-impedance spectroscopy experimental set-up, direct correlations of the degree of
phase transformation (expressed as change of the FWHM of the selected reflection) with electric
conductivity was found. Independent XRD measurements and full pattern fitting allowed
quantitative estimations of the phase composition of the spinels. It was found that commercial
spinels were in fact multiphase, with the content of the additional phase of few weight percent.
Evolution of the Fe3Si Phase during Siliconising of Ferrous Materials
Authors: Stergioudi F. , Tsipas D.N.
Published: March 2009

The evolution of the Fe-Si phase’s formation during siliconising of ferrous material was studied. The examined coatings were formed at 990 oC, via chemical deposition of Si in fluidized bed reactor (FBR). The substrate used for this purpose was carbon steel, ST37. Coatings of 10-50 μm thickness were obtained. Optical micrograph (OM) SEM analysis, as well as XRD measurements were used for coatings characterization. During an annealing process of the as formed coatings an ordering of the solid solution of α-FeSi was observed. The ordering process was found to be continuous and the phase gradually becomes super saturated. A narrow portion of the X-ray diagrams including the 110 and the 220 reflections of the α -Fe and α-Fe3Si was chosen for data elaboration.
Structure Studies of Electrodeposited Ni-Mo Alloys with Polymers after Annealing
Authors: Karolus Małgorzata , Rówiński Edward , Łągiewka Eugeniusz
Published: March 2009

Electrolytical layers of Ni-Mo alloys with polypyrrole, polytiofene and polyethylene were deposited on steel substrate (St3S, 4 cm2). After structural analyses of as quenched samples performed by X-ray diffraction it was noticed that the solid solution of Mo in Ni is observed. After annealing in an argon atmosphere the solid solution of Mo in Ni is becomeing more stable and crystalites are growing to the size of 200 – 300 Å. After annealing in an air atmosphere X-ray diffraction patterns show presence of phases: NiO, MoO, NiCO3, Mo2N. The unit cell parameters of solid solution after annealing are smaller than parameters of as quenched samples what means that the solid solution has been decomposing.
Vacancy Clusters in Germanium
Authors: Peaker Anthony R. , Markevich Vladimir P. , Slotte J. , Kuitunen K. , Tuomisto F. , Satta A. , Simoen Eddy , Capan I. , Pivac B. , Jačimović R.
Published: March 2009

Fast neutron irradiation of germanium has been used to study vacancy reactions and
vacancy clustering in germanium as a model system to understand ion implantation and the vacancy
reactions which are responsible for the apparently low n-type doping ceiling in implanted
germanium. It is found that at low neutron doses (~1011cm-2) the damage produced is very similar
to that resulting from electron or gamma irradiation whereas at higher doses (> 1013cm-2) the
damage is similar to that resulting from ion implantation as observed in the region near the peak of
a doping implant. Electrical measurements including CV profiling, spreading resistance, Deep-
Level Transient-Spectroscopy and high resolution Laplace Deep-Level Transient-Spectroscopy
have been used in conjunction with positron annihilation and annealing studies. In germanium most
radiation and implantation defects are acceptor like and in n-type material the vacancy is negatively
charged. In consequence the coulombic repulsion between two vacancies and between vacancies
and other radiation-induced defects mitigates against the formation of complexes so that simple
defects such as the vacancy donor pair predominate. However in the case of ion implantation and
neutron irradiation it is postulated that localized high concentrations of acceptor like defects
produce regions of type inversion in which the vacancy is neutral and can combine with itself or
with other radiation induced acceptor like defects. In this paper the progression from simple
damage to complex damage with increasing neutron dose is examined.
Infrared Absorption from Low Carbon Concentration, Low Dose, Annealed CZ Silicon
Authors: Inoue N. , Goto Y. , Sugiyama T.
Published: March 2009

Complexes formed by low dose irradiation with electron (1015-16/cm2) and He (5x1012-
5x1013/cm2) in the relatively low carbon concentration (1016/cm3) MCZ silicon were investigated by
highly sensitive and quantitative IR absorption analysis. CiOi and VO were the main complexes in
all cases. The concentration of these complexes was about 1015/cm3, or 10% of included carbon in
the highest case. Loss of almost equal amount of Cs was observed. The concentration of CiOiI was
one order of magnitude lower. Upon annealing, these lines weakened and almost disappeared at 400
oC. There were some absorption lines introduced by the annealing. VO2 was strongest among them
and CsOi related structure was also confirmed. There were absorption lines at 954.9 and 962.6 cm-1
appeared after annealing at 300 oC.
Divacancy Induced Improvement for Stabilization of Silicon Conductivity versus Temperature
Authors: Kamaev G.N. , Efremov M.D. , Stuchinsky V.A. , Mihailov B.I. , Kurkin S.G.
Published: March 2009

In present work temperature stable conductivity is considered for neutron-doped
FZ silicon with point radiation defects. It was shown that divacancy formed after electron
irradiation allow to increase resistivity of silicon at room temperature, what lead to less
variation of conductivity in a range of temperatures 20-160C. Discrepancy between
experimental and theoretical data was evaluated and corrected with introduction in the
model deep level center Ec-0.6eV. As result of investigation power resistors were
elaborated with 10% deviation from nominal value within the range of temperatures.
The Electrical and Optical Properties of Point and Extended Defects in Silicon Arising from Oxygen Precipitation
Authors: Jones R.
Published: March 2009

Oxygen precipitation in Si is a complex set of processes which has been studied over many
years. Here we review theoretical work relating to the precipitation process. At temperatures
around 450°C oxygen atoms become mobile and form a family of thermal double donors. The
structure of these defects and the origin of their electrical activity is discussed. At temperature
around 650°C these donors disappear and there is a growth of SiO2 precipitates along with rod
like defects which are extended defects involving Si interstitials. At higher temperatures these
collapse into dislocation loops. The structure and electrical properties of the rod like defect are
described and compared with those of dislocations.
First Principles Calculations of the Formation Energy of the Neutral Vacancy in Germanium
Authors: Śpiewak P. , Kurzydlowski Krzysztof Jan , Sueoka Koji , Romandic Igor , Vanhellemont Jan
Published: March 2009

Density functional theory (DFT) with local density approximation has been used to
calculate the formation energy (EF) of the neutral vacancy in germanium single crystal. It was
shown that careful checking of convergence with respect to the number of k-points is necessary
when calculating the formation energy of the intrinsic point defects in Ge. The formation energy of
the single neutral vacancy was estimated at 2.35 eV which is in excellent agreement with published
experimental data.
Primary Defects in n-Type Irradiated Germanium: A First-Principles Investigation
Authors: Carvalho A. , Jones R. , Janke C. , Öberg Sven , Briddon Patrick R.
Published: March 2009

The properties of point defects introduced by low temperature electron irradiation
of germanium are investigated by first-principles modeling. Close Frenkel pairs, including the
metastable fourfold coordinated defect, are modelled and their stability is discussed. It is found
that damage evolution upon annealing below room temperature can be consistently explained
with the formation of correlated interstitial-vacancy pairs if the charge-dependent properties of
the vacancy and self-interstitial are taken into account. We propose that Frenkel pairs can trap
up to two electrons and are responsible for conductivity loss in n-type Ge at low temperatures.
A Theoretical Study of Copper Contaminated Dislocations in Silicon
Authors: Fujita N. , Jones R. , Öberg Sven , Briddon Patrick R. , Blumenau A.T.
Published: March 2009

Recently, the interaction of copper with dislocations in p-type Si/SiGe/Si structures
has been investigated experimentally and a new dislocation related DLTS-level at Ev +0.32 eV
was detected after intentional contamination with copper. To determine the origin of this newly
detected level, in this work we present first density functional calculations of substitutional
copper at 90◦ and 30◦ partial dislocations in silicon. Defect–dislocation binding energies are
determined and electrical gap levels are calculated and compared with the experimental data.
As a result, the observed level at Ev + 0.32 eV is tentatively assigned to the single acceptor
level of substitutional copper at the dislocation.
Effect of Hydrostatic Pressure on Self-Interstitial Diffusion in Si, Ge, Si Crystals: Quantum-Chemical Simulations
Authors: Gusakov Vasilii E. , Belko V.I. , Dorozhkin N.N.
Published: March 2009

A theoretical modeling of the diffusion of self-interstitials in silicon and germanium crystals both at normal and high hydrostatic pressure has been carried out using molecular mechanics, semiempirical (PM3, PM5) and ab-initio (SIESTA) methods. According to the simulation for the Si and Ge neutral interstitials (I0) both in silicon and germanium crystals more stable configuration is <110> split interstitial. T is the stable configuration for the double positive interstitial I++, but the interstitial is displaced from the high-symmetry site. Stability of <110> splitinterstitial is not changed under hydrostatic pressure. The activation barriers for the diffusion of interstitials were determined and equal to ΔEa(Si)(<110> -> T1)=0.69 eV; ΔEa (Ge)(<110> -> T1)=1.1 eV. For mixed interstitials the calculated activation barriers equal Si Emix = 1.06 eV, Ge Emix = 0.86 eV. Hydrostatic pressure decreases the activation barriers ΔEa(Si), ΔEa (Ge).
Integrated Approach for Modeling of Heat Transfer and Microdefect Formation during CZ Silicon Single Crystal Growth
Authors: Prostomolotov A.I. , Verezub N.A.
Published: March 2009

The features of microdefect formation during dislocation-free Si single crystals are
considered in connection with the specific thermal CZ growing conditions. For this purpose the
thermal crystal growth histories are calculated by means of a global thermal mathematical model
and then on their basis the intrinsic point defect recombination and microdefect formation are
modeled numerically. Difficulty of such integrated approach is explained by of the complicated and
conjugated thermal modeling and a presence of various temperature zones in growing single crystal,
answering to various defect formation mechanisms.
Electrical Uniformity of Direct Silicon Bonded Wafer Interfaces
Authors: Wagener Magnus C. , Zhang R.H. , Zhao W. , Seacrist M. , Ries M. , Rozgonyi George A.
Published: March 2009

This paper describes a series of electrical measurements and sample modifications that
enabled the electrical properties of hybrid-orientation direct silicon bonded wafer interfaces to be
determined. It is shown that the carrier transport across this near-surface (110)Si/(100)Si boundary
is dictated by the defects present at the bond interface. These interface states are believed to pin the
Fermi-level, producing a conduction barrier with a thermal activation energy Ea = 0.56eV. The
defect band has been identified by deep-level transient spectroscopy and associated with the defect
states typically observed in plastically deformed silicon. The carrier transport behavior across the
bonding interface, as well as the observed interface trap levels are therefore attributed to the
dislocation network present at the bonding interface. The spatial uniformity of the interface
properties have been evaluated by TEM, electron-beam induced current microscopy,
photoconductive decay and conduction measurements.
The Role of High Temperature Treatments in Stress Release and Defect Reduction
Authors: Mica Isabella , Polignano Maria Luisa , Bonera Emiliano , Carnevale Gian Pietro , Magni P.
Published: March 2009

In this work we discuss an original analysis about a method to reduce the dislocation
density in the devices that use the Shallow Trench Isolation (STI). It is well known that a high
mechanical stress in silicon combined with an amorphizing implantation damage can generate many
dislocations. So we propose to release the mechanical stress in silicon before implanting. A high
temperature treatment indeed can trigger the viscous behaviour of the filling oxide inducing the
relaxation of the stress field in silicon. For the first time a systematic study of the effect of different
furnace and RTP annealings in the stress relaxation was done by Raman measurements. Different
temperatures (from 3000C to 11000C) and different durations (from few seconds to one hour) were
explored and the experimental results were compared with the numerical simulation with a good
agreement. Finally we study the effect of the most promising annealings selected by Raman in a
complete process flow.
Radiation Enhanced Diffusion of Implanted Palladium in Silicon
Authors: Vobecký Jan
Published: March 2009

Low-temperature diffusion of palladium (450–700 oC) from an implanted layer
(9.5 MeV, 1⋅1013cm-2) deep into the volume of a high-power P-i-N diode (2.5kV, 150A) is
compared with that of a sputtered palladium layer (50nm thick), both under the enhancement by the
radiation defects from He2+ implantation (10 MeV, 1⋅1012cm-2). Annealing after the palladium
implantation (800oC, 60min.) prior to the He2+ implantation is shown to increase the concentration
of palladium related deep levels in the damaged region with a subsequent improvement of diode
dynamic parameters. The concentration of palladium in-diffusing from the implanted layer with the
dose of 1⋅1013cm-2 does not sufficiently reduce excess carrier lifetime close to the anode junction as
is the case of the devices with sputtered palladium that give better dynamic parameters like lower
maximal reverse recovery current and recovery losses for the same magnitude of leakage current.
Horizontal Versus Vertical Annealing of Silicon Wafers at High Temperatures
Authors: Kissinger G. , Fischer A. , Ritter G. , Akhmetov V.D. , Kittler Martin
Published: March 2009

The gravitational induced shear stresses in 200 mm silicon wafers supported in verticaltype
or horizontal-type furnace were calculated using 3D-FEM analysis of the displacement vector
assuming linear elastic behavior of the anisotropic material. For comparison of the two complex
loading cases and for relating the effect of gravitational constraints to the mechanical strength of the
wafers, the invariant von Mises shear stress τM was chosen. The computed maximum values of τM
demonstrate that the gravitational induced stress for vertical processing is approximately one order
of magnitude less than the gravitational induced stress for horizontal processing. The experimental
results obtained from processing of 200mm wafers with different oxygen concentration in
horizontal and vertical boats at 1200°C are in an excellent agreement with the theoretical
simulations.
Impact of Extended Defects on the Electrical Properties of Solar Grade Multicrystalline Silicon for Solar Cell Application
Authors: Binetti Simona , Acciarri Maurizio , Libal Joris
Published: March 2009

Aim of this work is to study the electrical properties and the minority charge carrier
recombination behaviour of extended defects in multicrystalline silicon (mc-Si) ingots grown from
solar grade silicon (SoG-Si) feedstock. The pure metallurgical SoG-Si feedstock has been produced
directly by carbothermic reduction of very pure quartz and carbon without subsequent purification
processes.This mc SoG-Si is studied by temperature-dependent Electron Beam Induced Current
measurements and PhotoLuminescence spectroscopy and the potentiality of the combination of
these two techniques in the identification of the defects which limit the quality of the base material
is shown. The EBIC mapping technique shows the presence of electrically active grain boundaries at
room temperature while dislocations result inactive. Dislocations become active only at
temperatures lower than 250K, indicating a moderate level of metal decoration. The most
detrimental defects in this material seem to be the grain boundaries and impurities dissolved in the
matrix. Furthermore, the PL spectra reveal the presence of oxygen and carbon related complexes. In
this work we show that the knowledge about the defect related recombination processes acquired by
a combined application of EBIC measurements and PL-spectroscopy is of particular importance to
tune the proper solar cell process step to be applied on such material.
HREM Study of the Strain Field Induced by the Entrance of a Matrix Dislocation within the Coherent Twin GB in Ge.
Authors: Thibault-Pénisson Jany , Hÿtch Martin J.
Published: March 2009

Strains around a constricted matrix dislocation in a coherent twin grain boundary in
germanium is measured by a combination of high-resolution electron microscopy and geometric
phase analysis. Whilst strains in the grains on either side of the twin boundary agree closely with the
isolated dislocation case, significant additional strains are localized at the boundary plane. By
comparing the stresses and strains across the boundary plane, values for the elastic modulus of the
twin boundary are determined. They are found to exhibit a drastic decrease as compared to the bulk
and this is interpreted in terms of the non-equilibrium configuration of the boundary.
Nanoscale Imaging of CaCu3Ti4O12 Dielectric Properties: The Role of Surface Defects
Authors: Raineri Vito , Fiorenza Patrick , Lo Nigro Raffaella , Sinclair Derek C.
Published: March 2009

Scanning probe microscopy with conductive tips has been used to image the dielectric
properties of ceramics with giant permittivity. In particular, measurements in impedance mode and
of local resistivity allowed to image the permittivity map on polycrystalline materials. Such imaging
allows to correlate the dielectric properties with the local sample structure and with defects inside
the single grains of the polycrystalline ceramics. However, artifacts due to surface imperfections
should be distinguished from bulk properties and eliminated.
Vacancies in Growth-Rate-Varied CZ Silicon Crystal Observed by Low-Temperature Ultrasonic Measurements
Authors: Yamada-Kaneta Hiroshi , Goto Terutaka , Nemoto Yuichi , Sato Koji , Hikin Masatoshi , Saito Yasuhiro , Nakamura Shintaro
Published: March 2009

The low-temperature ultrasonic experiments are performed to measure the distribution of vacancy
concentration in the ingot of the Czochralski (CZ) silicon crystal grown with the pulling rate
gradually lowered. The elastic softening similar to that we recently found for the
floating-zone-grown silicon crystals is observed for the so-called vacancy-rich region of the ingot
which contains no voids or dislocation clusters. We further uncover that the interstitial-rich region
in the ingot exhibits no such elastic softening, confirming our previous conclusion that the defects
responsible for the low-temperature elastic softening are the vacancies. We also disclose that the
elastic softening is absent for the ring-like oxidation stacking fault (R-OSF) region of the ingot. The
measured distribution of the vacancy concentration indicates that the minority point defects are
perfectly cancelled by the majority point defects during the CZ crystal growth.
Photoinduced Variation of Capacitance Characteristics of MDS Structures with Three-Layer SiNx Dielectrics
Authors: Arzhannikova Sofia A. , Efremov M.D. , Volodin Vladimir A. , Kamaev G.N. , Marin D.V. , Shevchuk V.S. , Kochubei S.A. , Popov A.A. , Minakov Yu. A.
Published: March 2009

Characterisation of three-layer dielectric embedded into MDS-structure (Metal-
Dielectric-Silicon) was provided in the dark and under light illumination. In the dark, increasing of
differential capacitance, simultaneously, with variation of differential conductivity of MDSstructures
was detected. In the light strong changing of capacitance part of impedance was firstly
observed, demonstrating decreasing almost to zero values and restoring up to maximal values in
narrow bang of voltage applied. Variation of capacitance exceeds significantly so called dielectric
layer capacitance, what interpreted as carriers exchanging between substrate and electronic states in
SiNx probably due to three-layered kind of its nature.
Metal In-Diffusion during Fe and Co-Germanidation of Germanium
Authors: Simoen Eddy , Opsomer K. , Claeys Cor , Maex Karen , Detavernier Christophe , Van Meirhaeghe R.L. , Clauws Paul
Published: March 2009

In this paper, the deep levels occurring in Fe- or Co-germanide Schottky barriers on ntype
Ge have been studied by Deep Level Transient Spectroscopy (DLTS). As is shown, no traps
have been found for germanidation temperatures up to 500 oC, suggesting that in both cases no
marked metal in-diffusion takes place during the Rapid Thermal Annealing (RTA) step. Deep
acceptor states in the upper half of the Ge band gap and belonging to substitutional Co and Fe can
be detected by DLTS only at higher RTA temperatures (TRTA). For the highest TRTA, deep levels
belonging to other metal contaminants (Cu) have been observed as well. Simultaneously, the reverse
current of the Schottky barriers increases with TRTA, while the barrier height is also strongly
affected.
Clustering of Gold on 6H-SiC and Local Nanoscale Electrical Properties
Authors: Ruffino Francesco , Giannazzo Filippo , Roccaforte Fabrizio , Raineri Vito , Grimaldi Maria Grazia
Published: March 2009

In this work, a methodology, based on a self-organization process, to form gold
nanoclusters on the 6H-SiC surface, is illustrated. By scanning electron microscopy and atomic
force microscopy the gold self-organization induced by annealing processes was studied and
modelled by classical limited surface diffusion ripening theories. These studies allowed us to
fabricate Au nanoclusres/SiC nanostructured materials with tunable structural properties.
The local electrical properties of such a nanostructured material were probed, by conductive atomic
force microscopy collecting high statistics of I-V curves. The main observed result was the
Schottky barrier height (SBH) dependence on the cluster size. This behaviour is interpreted
considering the physics of few electron quantum dots merged with the ballistic transport. A quite
satisfying agreement between the theoretical forecast behaviour and the experimental data has been
found.
On the Failure of Intelligent Power Devices Induced by Extreme Electro-Thermal Fatigue. A Microstructural Analysis
Authors: Khong Benjamin , Legros Marc , Dupuy Philippe , Levade Colette , Vanderschaeve Guy
Published: March 2009

Microstructural analysis of power devices were carried out on components from
Freescale Semiconductor that underwent extreme electro-thermal fatigue. Several destructive and
non destructive techniques were used. It is shown that the main cause of devices failure is
delamination between the heat sink and the power die. Additional causes of failure are identified.
The fatigue-induced modifications of the structure of the metallization layer (grain growth, grain
boundary grooving) is also discussed.
Properties of Nanostructure Formed on SiO2/Si Interface by Laser Radiation
Authors: Medvid Arthur , Dmitruk Igor , Onufrijevs Pavels , Pundyk Iryna
Published: March 2009

The aim of this work is to study optical properties of Si nanohills formed on the SiO2/Si
interface by the pulsed Nd:YAG laser radiation. Nanohills which are self-organized on the surface
of Si, are characterized by strong photoluminescence in the visible range of spectra with long wing
in the red part of spectra. This peculiarity is explained by Quantum confinement effect in nanohillsnanowires
with graded diameter. We have found a new method for graded band gap semiconductor
formation using an elementary semiconductor. Graded change of band gap arises due to Quantum
confinement effect.
Size Dependent Photoluminescence of Si Nano-Crystals Embedded in Amorphous Silicon
Authors: Vasques A.L. Quintos , Torchynska T.V. , Polupan G. , Matsumoto-Kuwabara Y. , Khomenkova L. , Shcherbyna L.V.
Published: March 2009

This paper presents the results of PL spectrum studies for Si nano-crystallites embedded
in amorphous silicon matrix. Investigated layers were deposited by the hot-wire CVD method on
glass substrates at the wafer temperature 300°C and different filament temperatures from the range
1650-1950°C. It was shown that variation of temperatures of filament (hot-wire) allows to produce
the films with desirable parameters. Using of X-ray diffraction and photoluminescence methods the
correlation between some photoluminescence bands and the sizes of Si nano-crystallites as well as
the amorphous phase volume was shown. The nature of light emission is discussed.
Study of the Dynamics of Local Particle Removal Efficiencies Using Localized Haze Maps
Authors: Janssens Tom , Holsteyns Frank , Kenis Karine , Arnauts Sophia , Bearda Twan , Wostyn Kurt , Simpson Gavin , Steinbach Andy , Mertens Paul W.
Published: March 2009

The local particle removal efficiency (PRE) of nano particles in megasonic cleaning experiments is
studied. This approach makes it possible to quantify non uniform cleaning effects over the wafer
and to look into the dynamics of particle removal at different areas on the wafer. A direct correlation
between PRE and megasonic induced damage of device structures demonstrates that a considerable
amount of damage is already formed at less efficiently cleaned areas of the wafer.
Effect of Ozone Supply Methods on PRE in Alkaline Ozone Solutions
Authors: Lee Seung Ho , Kim Tae Gon , Kwon Tae Young , Park Jin Goo , Bae So Ik , Lee Gun Ho , Kim In Jung
Published: March 2009

Ozonated DI water was supplied to make alkaline cleaning solutions to replace SC1 chemicals in a bath with and without recirculation. With recirculation, low dissolved ozone and low pH cause lower particle removal efficiency (PRE) of 75%. However, direct supply of ozonated water with NH4OH to a bath without recirculation resulted in higher PRE over 93 %.
Marangoni Dryer Integrated High Performance Cleaner for Cu/Low k Post Strip Clean for 45nm Technology Node and Beyond
Authors: Tang Jian She , Lu Wei , Xi Bo , Martinez Eli , Li Fred , Ko Alex , Todd Craig , Lee John T.C.
Published: March 2009

To address the water mark issue from hydrophobic film drying, and the stringent particle removal requirements for the 45nm technology node and beyond, we developed a cleaner with an innovative single wafer Marangoni dryer. The single wafer Marangoni dryer design features and process characterization data are presented in this paper. The major results can be summarized as: (1) With the immersion type Marangoni dryer, as the wafer is lifted out of a DIW bath, a stable and uniform meniscus can be easily maintained, making the single-wafer Marangoni dryer ideal for drying hydrophilic, hydrophobic or hydrophobic/hydrophilic mixed patterned wafers; (2) The new Marangoni dryer leaves ~14nm [1] water film on the wafer after drying, therefore any dissolved or suspended materials contained inside the water film, and potentially left on the wafer surface after water evaporation, is less than 14nm in diameter. This feature is critical for the 45nm technology node and beyond because 23nm particle could be killer defects at these nodes [2]; (3) Because of the strong Marangoni flow effect, high aspect ratio features can be completely dried without leaving any water droplets inside the trenches; therefore copper corrosion can be prevented; (4) The Marangoni dryer uses N2 as the carrier gas, so when a wafer is lifted out of the degasified DIW bath through the N2/IPA spray zone, it is thoroughly dried in an oxygen-free environment before exposure to the ambient environment; (5) The Marangoni dryer is free of electrostatic charge and centrifugal force because of the slow (2mm/s~20mm/s) wafer linear lifting speed compared to linear speed at wafer edge during SRD.
A Passive Film Formed on Alloy 600 in High Temperature Aqueous Solution
Authors: Kim Dong Jin , Kwon Hyuk Chul , Hwang Seong Sik , Kim Hong Pyo
Published: March 2009

Alloy 600(74wt% Ni, 15wt% Cr, 9wt% Fe) is used as a material for steam generator
tubing in pressurized water reactors(PWR) due to its high corrosion resistance under a PWR
environment whose primary side and secondary side are operated under 340oC, 150bar and 290oC,
50bar, respectively. However, in spite of its outstanding corrosion resistance, a stress corrosion
cracking(SCC) which has been one of the most important degradation issues, has occurred
occasionally owing to the severe high temperature and pressure condition of a PWR. It is expected
that a SCC is deeply related to an electrochemical property of a passive film formed under a high
temperature and pressure condition. Therefore an understanding of the basic electrochemical
behaviors regarding an anodic dissolution and a passivation of the bare surface of metals and alloys
provides important information about a SCC mechanism and control. In the present work, the
passive oxide films on Alloy 600 were investigated as a function of the dissolved oxygen content
and the pH by using a potentiodynamic polarization, electrochemical impedance spectroscopy(EIS)
and a depth profiling by Auger electron spectroscopy(AES). For this purpose, 0.5M H3BO3, 0.5M
Na2SO4 and 0.1M NaOH aqueous solutions with/without dissolved oxygen at 300oC were used as
the test solutions. The resistance of an oxide formed in an aerated solution was smaller than that in a
deaerated solution while the oxide film in the aerated solution was thicker than the oxide film in the
deaerated solution.
Effect of Vanadium on Development of Acicular Ferrite Microstructure in Low Carbon Steel
Authors: Jin Hyung Ha , Shin Chan Sun , Lee Hu Chul
Published: March 2009

The influence of vanadium on the development of an acicular ferrite microstructure has
been investigated in a low carbon steel. Optical and electron microscopy were carried out to identify
the precipitates, inclusions and constituents of the acicular ferrite microstructures. By the addition
of vanadium, the main microstructural constituent was changed from a side plate ferrite to an
acicular ferrite. VCN precipitates, which were known to favor the nucleation of acicular ferrite,
were formed on the (Mn,Si) oxide and MnS particles. The presence of vanadium in alloys
suppressed the formation of a side plate ferrite and reduced the transformation of ferrite during an
isothermal transformation. Nucleation of intragranular ferrite and a subsequent sympathetic
nucleation of ferrite within austenite grains were favored in the vanadium containing steel and an
acicular ferrite microstructure was developed.
Microstructure and Nano-Indentation Properties of Ion-Irradiated Fe-9wt%Cr Alloy
Authors: Jin Hyung Ha , Shin Chan Sun , Kim Wheung Whoe
Published: March 2009

A change of the mechanical property and microstructure of an Fe ion irradiated polycrystalline Fe-9wt%Cr model alloy to 1 dpa was examined using a nano-indentation and transmission electron microscopy. We anticipated that irradiated damage would be formed up to about 2.5μm and a displacement damage peak would be located at around 1.7μm from a surface through a TRIM code calculation. A thick dark band was formed at about 1.5μm from a surface with an actual TEM observation, which is consistent with a displacement damage peak in the TRIM code calculation. TEM observations showed that small defects with a Burgers vector a0<100> and 1/2a0<110> are formed in irradiated Fe-9wt%Cr alloy. In the nano indentation test, the hardness increase due to irradiation induced defects was up to 0.6GPa which can be converted to a yield stress increase of 200MPa.
Colloidal Crystal Templating of Two-Dimensional Ordered Macroporous SiCN Ceramics
Authors: Song In Hyuck , Kim Yong Jin , Kim Hai Doo , Kim Dong Pyo
Published: March 2009

In this study, two-dimensional (2D) ordered macroporous SiCN ceramics were prepared
by infiltrating sacrificial colloidal silica (SiO2) templates with the low molecular weight preceramic
polymer, polysilazane. This was followed by a thermal curing step, pyrolysis at 1250°C in a N2
atmosphere, and finally the removal of the templates by etching with diluted HF. In particular,
100large-scale monolayer silica crystals were prepared on the cleaned Si substrates by spin coating.
Two-dimensional SiCN ordered pore arrays were fabricated by a solution-dipping template strategy.
Reflectometry Studies of Mesoporous Silica Thin Films
Authors: Hwang Young Kyu , Mamman Ajit Singh , Patil K. R. , Kim Lee Kyung , Hwang Jin Soo , Chang Jong San
Published: March 2009

Reflectometry technique has been successfully applied to investigate the correlation between the porosity and optical property (refractive index) of the ordered mesoporous thin film deposited on silicon wafer substrates. The measured optical spectra were simulated by the Effective Medium approximation model. The reflectometry technique has been found to be appropriate for the measurement of thickness of thin films as well as thick layer films. The mesoporous silica films prepared from tri-block copolymer (F-127) as a surfactant and polypropylene oxide as a swelling agent were subsequently exposed to the ammonia vapors to enhance thermal stability and shrinkage minimization of the film that results in increased film thickness.
Thermal Behaviors and Fracture Toughness of Polyurethane-Dispersed Difunctional Epoxy Resins
Authors: Park Soo Jin , Lee Jae Rock
Published: March 2009

In this work, the thermal and mechanical interfacial properties of diglycidylether of bisphenol A (DGEBA)/polyurethane modified epoxy (UME-305) blends were investigated. 4,4’-Diaminodiphenyl methane (DDM) was used as a curing agent, and the content of UME-305 in the mixture was 0, 20, 40, 60, 80, and 100 wt%. The cure behaviors of DGEBA/UME-305 blends were studied by DSC. The mechanical interfacial properties were confirmed by critical stress intensity factor (KIC) at 77K and 298K. As a result, the exothermic peaks in DSC results were shifted to higher temperature region as increasing the UME-305 content in the blends. The KIC was also enhanced with increasing the UME-305 content and showing a maximum value at 60 wt.% UME-305.