bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evolution Of Defects Induced By High Energy He Implantation In Gold-Diffused Silicon
Authors: Bouayadi R. El , Regula G. , Pichaud B. , Lancin M. , Simon J. J. , Ntsoenzok E. 
Published: April 2011

ABSTRACTSilicon samples were gold-diffused at different temperatures, implanted with He ions at 1.6 MeVand then annealed at 1050°C for 2 hours. The implantation induced-defect structure and their distributionin the depth of the sample, studied by conventional and high resolution cross section electron microscopy (HRXTEM) depend on the gold level introduced in the wafer prior to the gettering process. A high concentration of gold in silicon seems to influence the defect configuration in the cavity zone. Indeed, gold chemisorbed atcavities can homogenize the surface energy of their planes in different orientations, and can increase the cavity critical diameter beyond they become facetted. Secondary ion mass spectroscopy (SIMS) profiles exhibit ashouldered shape and a width closely related to the presence of the defects (observed by XTEM) which are veryefficient sinks both for gold and copper atoms. Unfortunately, the electrical improvement of the material (checked by minority carriers diffusion length measurements MCDL) is not achieved by this gettering process, probably due to the high metal impurity concentrations remaining out of the gettering zone, to the presence of AuCu complexes and η-Cu3Si precipitates identified by deep level transient spectroscopy (DLTS)measurements and HRXTEM observations respectively.
Defect Evolution from Low Energy, Amorphizing, Germanium Implants on Silicon
Authors: Gutierrez Andres F. , Jones Kevin S. , Downey Daniel F. 
Published: April 2011

ABSTRACTPlan-view transmission electron microscopy (PTEM) was used to characterize defect evolution upon annealing of low-to-medium energy, 5-30 keV, germanium implants into silicon. The implant dose was 1 × 1015 ions/cm2, sufficient for surface amorphization. Annealing of the samples was done at 750 °C in nitrogen ambient by both rapid thermal annealing (RTA) and conventional furnace, and the time was varied from 10 seconds to 360 minutes. Results indicate that as the energy drops from 30 keV to 5 keV, an alternate path of excess interstitials evolution may exist. For higher implant energies, the interstitials evolve from clusters to {311}'s to loops as has been previously reported. However, as the energy drops to 5 keV, the interstitials evolve from clusters to small, unstable dislocation loops which dissolve and disappear within a narrow time window, with no {311}'s forming. These results imply there is an alternate evolutionary pathway for {311} dissolution during transient enhanced diffusion (TED) for these ultra-low energy implants.
Carbon Diffusion and Clustering in SiGeC Layers Under Thermal Oxidation
Authors: Salvador D. De , Napolitani E. , Coati A. , Berti M. , Drigo A.V. , Carroll M. , Sturm J.C. , Stangl J. , Bauer G. , Lazzarini L. 
Published: April 2011

ABSTRACTIn this work we investigated the diffusion and clustering of supersaturated substitutional carbon 200nm thick SiGeC layers buried under a silicon cap layer of 40nm. The samples were annealed in inert (N2) or oxidizing (O2) ambient at 850°C for times ranging from 2 to 10 hours. The silicon self-interstitial (I) flux coming from the surface under oxidation enhances the C diffusion with respect to the N2 annealed samples. In the early stages of the oxidation process, carbon escape by diffusion across the layer/cap interface dominates. This phenomenon saturates after an initial period (2-4h) which depends on the C concentration. This saturation is due to the formation and growth of C containing precipitates which are promoted by the I injection and act as a sink for mobile C atoms. The competition between clustering and diffusion is discussed for two different C concentrations.
Implant Dose and Spike Anneal Temperature Relationships
Authors: Bourdelle K. K. , Fiory A. T. , Gossmann H.-J. L. , McCoy S. P. 
Published: April 2011

ABSTRACTThe method of ion implantation and spike annealing for preparing shallow junctions suitable for the extension regions bridging the channel and source/drain contacts of CMOS transistors are studied by annealing blanket implants. Junction depths at a given sheet resistance for low energy B implants are minimized for the combination of a fast ramp with a sharp-spike anneal. This is shown to be physically based on activation energy phenomenology. The fraction of electrically activated B is insensitive to implant dose, unlike the case of transient enhanced diffusion. Arsenic implants show higher activation fraction than comparably annealed P implants, without the large transient enhanced diffusion which is attributed to P and Si-interstitial coupled diffusion. For targeted sheet resistance and junction depth, spiking temperature trends lower with implant dose, concomitant with decreasing fraction of activated dopant.
Reverse Diode Leakage in Spike-Annealed Ultra-Shallowjunctions
Authors: Gossmann Hans-Joachim L. , Feng Tao , Agarwal Aditya , Frisella Peter , Rubin Leonard M. 
Published: April 2011

ABSTRACTWe have investigated diode leakage in junctions produced by ion-implantation of B with energies of 0.5 - 2 keV and doses of 2 × 1014 — 2 × 1015 cm−2 into n-type wells of ∼1 × 1018 cm−3, after rapid-thermal anneals (RTA) in lamp-based and hot-wall furnaces. Junc- tions are as shallow as 30nm and were directly probed to avoid complications arising from metalization. The leakage current, Ilkg, was found to be independent of the implant dose at any reverse voltage (-1 and -5 V). This implies that the electrically active defects are sufficiently far removed and on the surface-side of the junction. In both systems, a spike anneal (no intentional dwell time at peak-temperature) resulted in higher Ilkg than a soak anneal (dwell time of several seconds at peak-temperature). However, for the same spike annealing recipe, the hot-wall RTA produces tighter distributions than the lamp-based RTA. The width of the distribution is a mea- sure of the temperature uniformity across the wafer. Best leakage currents are of the order 1 × 10−6 A/cm2, in good agreement with device simulations The shallowest junctions exhibit Ilkg ∼5 × 10−4 A/cm2, still well below the specification of even the low power transistor of a 100 nm technology.
Boron Solubility Limits Following Low Temperature Solid Phase Epitaxial Regrowth
Authors: Lindfors C. D. , Jones K. S. , Rendon M. J. 
Published: April 2011

ABSTRACTThe work described herein focuses on examining the effect of solid phase epitaxial regrowth (SPER) on boron implanted silicon. It is shown that boron levels within the silicon can greatly enhance or reduce the regrowth rate of the silicon. Electrical measurements show optimum sheet resistances for 5 keV, 2×1015 cm−2 implant conditions yielding sheet resistance values of ∼140 Ω/sq at 500 °C annealing to ∼120 Ω/sq at 650 °C. Results using Hall effect and four-point probe show lower doses of boron will become fully active but levels will drop significantly as dose is increased. Lastly, maximum active concentrations of boron appear to reach values of ∼3-4×1020 cm−3 for a boron dose of 1×1015 cm−2 after SPER. Lower SPER anneal temperatures or higher doses tend to activate less boron.
Effects of Nano-scale Colloidal Abrasive Particle Size on SiO2 by Chemical Mechanical Polishing
Authors: Zhou Chunhong , Shan Lei , Ng S.H. , Hight Robert , Paszkowski Andrew. J. , Danyluk S. 
Published: April 2011

ABSTRACTThis paper reports on the effect of colloidal abrasive particle size in the polishing of thermally grown silicon dioxide on 100mm diameter, P-type, (100), single crystal silicon wafers. The abrasive particle sizes were varied in six (6) slurries with pH values of 10.97 ± 0.08. The abrasive sizes were 10, 20, 50, 80, 110 and 140nm in diameter, and the slurry contained 30 weight percent abrasives. The experimental results indicate that the material removal rate (MRR) varies with the volume of the particle size. Results also confirm that there exists an optimum abrasive particle size with respect to material removal rate and surface finish. For a pad surface roughness of 5.2μm (Ra), the slurry containing 80nm particles resulted in the highest material removal rate and best surface finish. A nano-film model based on the pad roughness is used to explain the results.
Engineered porous and coated Silica particulates for CMP applications
Authors: Choi K.S. , Vacassy R. , Bassim N. , Singh R. K. 
Published: April 2011

ABSTRACTThe aim of this study has been to synthesize the microporous silica spheres and to coat as-synthesized SiO2 with CeO2 for CMP applications. First, spherical microporous silica powders with a narrow size distribution have been prepared by a precipitation technique involving the hydrolysis reaction of a silicon alkoxide in ethanol. The interparticle microporosity has been created by adsorption of an organic compound (glycerol) as the porogen. The presence of glycerol during the synthesis affects considerably the precipitation mechanism and its effect on the particle size will be discussed. The synthesis of silica microporous spheres of narrow size distribution yielded the preparation, by varying particle size and porosity, of a wide range of aqueous silica slurries. The influence of particle size, particle size distribution, porosity and particle concentration will be discussed in chemical mechanical polishing applications. Although silica particles show large plastic deformation than the bulk material, very good glass polishing rates are obtained due to the plastic deformation of the silica layer during CMP. Silica particles are suitable candidates for application in CMP because silica can be directly precipitated as monodispersed spheres, their narrow size distribution being an important requirement in CMP applications. Secondly, as-synthesized silica particles were coated with the cerium dioxide particles having hexagonal shape, which were precipitated by decomposition from the cerium precursors. For this study, three coating processes were introduced to investigate the best coating parameters. Improvements in CMP of glass were also obtained by coating silica particles with cerium oxide nanoparticles.
Polishing and Cleaning of Low K Dielectric Material for ild and Damascene
Authors: Wang Yuchun , Bajaj Rajeev , Moon Yongsik , Mai David , Wijekoon Kapila , Chen Yufei , Redeker Fritz 
Published: April 2011

Summary:This paper describes CMP challenges in development of copper-low k process technology. As copper/oxide or copper/FSG backend schemes are being implemented successfully in early manufacturing, development focus has shifted to Cu/OSG (organo-silicate glass) integration development. Cu-OSG presents unique challenges with CMP integration, as these films tend to have much lower hardness than silicon dioxide. Significant process challenges have to be overcome prior to successfully implementing CMP process which does not mechanically damage the softer films and at the same time can achieve planarization requirements expected from CMP process. In addition, the OSG films tend to be hydrophobic leading to a need for developing improved cleaning processes/consumables. It was determined that Applied Materials ElectraPolishTM barrier slurry is extendable to OSG films. Good removal rate and removal profile can be achieved with ElectraPolishTM slurry. A proprietary cleaning solution reduced defect counts by 2 orders of magnitude as detected by SurfScan SS6200 on blanket OSG wafers. The same cleaning solution can be applied to copper/low-k patterned damascene wafers to clean both copper and dielectric surface. Polished OSG films have RMS roughness less than 2 angstroms and copper surface roughness about 5 angstroms with good surface finish. Blanket and patterned wafer results are presented to demonstrate final capability. Future directions for process enhancement are suggested.
An Integrated Molecular Dynamics and Monte Carlo Approach to Study Epitaxial Deposition of Silicon
Authors: Somasi Sweta , Khomami Bamin , Lovett Ronald 
Published: April 2011

ABSTRACTThe length and time scales of an atomistic simulation are often too small for any direct comparison with experimental observations. In order to study the coverage of pits (COPs) found on the Si (100) surface by epitaxial deposition, we first calculate rate of individual steps using molecular dynamics and then define a sequence of Monte-Carlo steps to study the effect of various factors on effective coverage of COPs.
Atomic Assembly of Giant Magnetoresistive Multilayers
Authors: Wadley Haydn N.G. , Zhou Xiaowang , Johnson Robert A. 
Published: April 2011

ABSTRACTThe emergence of metal multilayers that exhibit giant magnetoresistance (GMR) has led to new magnetic field sensors, and approaches for nonvolatile random access memories. Controlling the atomic scale structure across the many interfaces within these multilayers is central to improve the performance of these devices. However, the ability to manipulate atomic arrangements at this scale requires an understanding of the mechanisms that control heterometal film growth during vapor deposition. It is important to develop methods that enable prediction of the effects of deposition conditions upon this structure. Atomistic simulation approaches have been combined with deposition reactor models to achieve this. We have applied these approaches to analyze the atomic scale structure of sputter deposited CoFe/Cu/CoFe giant magnetoresistive multilayers similar to those used for magnetic field sensing. Significant intermixing is revealed at the CoFe-on-Cu interface, but not at the Cu-on-CoFe interface. Recent experiments verified these predictions. The insights provide a basis for the development of processes that inhibit thermally activated atomic diffusion while allowing the controlled use of the metal atom impact energy and inert gas ions to manipulate the structure of interfaces.
Nanoindentation and Microstructural Evolution Studies of DC Magnetron Sputtered Chromium Nitride Thin Films
Authors: Agarwal A.B. , Rainey B.A. , Yalisove S.M. , Bilello J.C. 
Published: April 2011

ABSTRACTNanoindentation experiments have been performed to assess the mechanical behavior of chromium nitride (CrxNy) thin films sputtered in different deposition geometries and with varying Ar and N2 pressures. The hardness and elastic modulus of chromium nitrides are of great interest with regard to their applications. In the present work, two different deposition geometries, i.e. multi-substrate and confocal, were used to sputter (DC magnetron) a CrxNy layer on Si (100) wafers at varying nitrogen flow rates. The results of the nanoindentation experiments indicate that, over a similar argon and nitrogen regime, the CrxNy films grown in a multi- substrate geometry exhibit higher hardness and elastic modulus on the average than those grown in the confocal geometry. Furthermore, it was found that in the multi-substrate geometry the hardness and elastic modulus of the films were significantly higher than those in the confocally deposited films for a specific regime of the nitrogen flow rate (10-14 sccm). Finally, observations of the mechanical properties trends could be correlated with a higher degree of anisotropic stress for films grown in the multi-substrate in comparison to the confocal geometry.
Effect Of RTA On TiN Films As The Barrier Layer for Pt/BST/Pt Capacitors Prepared By RF Magnetron Co-sputter Technique At Low Substrate Temperature
Authors: Juang Miin-Horng , Hwang Chuan-Chou , Cheng Huang-Chung 
Published: April 2011

ABSTRACTEffect of rapid-thermal-annealing on metallic barrier TiN against the interdiffusions of Ti and Si into BST in Pt/BST/Pt/TiN/Ti/Si capacitors has been studied. In the integration of BST capacitors, the thermal budget of the BST deposition would cause the inter-diffusions of Ti and Si from Ti adhesion layer and Si-plug respectively. This event would degrade the BST capacitors. To address this issue, rapid-thermal-annealed TiN barriers were used between the bottom electrode Pt and adhesion layer Ti. Optimal RTA condition for TiN were found in this experiment. Excellent electrical characteristics of Pt/BST/Pt/TiN/Ti/Si capacitors, including high dielectric constant (εr =320), low leakage current (1.5×10−8 A/cm2) under 0.1 MV/cm, and life time longer than 10 year lifetime under 1.6 MV/cm were obtained with Ar+O2 mixed ambient at a low substrate temperature (300°C).
Microstructure and Surface Evolution in the Crystallization of α-Fe2O3/α-Al2O3(0001) Thin Films
Authors: Cho Tae Sik , Doh Seok Joo , Je Jung Ho 
Published: April 2011

ABSTRACTWe found the correlation between microstructure and surface evolution in the crystallization of amorphous α-Fe2O3/α-Al2O3(0001) thin films using real-time synchrotron x-ray scattering and atomic force microscope. The amorphous precursor is crystallized to the epitaxial α-Fe2O3 grains in three steps; i) the growth of the well aligned α-Fe2O3 interfacial islands on α-Al2O3(0001), ii) the growth of the misaligned, homoepitaxial, α-Fe2O3 grains on the well aligned grains ( > 400 °C), and iii) the nucleation of the heteroepitaxial misaligned grains directly on the α-Al2O3substrate ( > 600 °C). The surface roughing is caused by the microstructure evolution during the crystallization of the amorphous precursor films.
The size effect of the polarization of SrBi2Ta2-xNbxO9 Capacitor
Authors: Tanaka Keisuke , Azuma Masamichi , Shimada Yasuhiro , Otsuki Tatsuo , Araujo Carlos A. Paz de 
Published: April 2011

ABSTRACTIt is known that the ferroelectric characteristic drastically changes between the bulk crystal state and the thin film state, fabricated for the high density FeRAM. Therefore, the theoretical clarification of the high density FeRAM characteristic has become very important to realize the next generation FeRAM devices on time.The size dependence of the polarization of SrBi2Ta2-xNbxO9 (SBTN) ferroelectric capacitor was calculated in the two-dimensional capacitor system considered with two different mechanisms, the depolarization effect and the surface effect due to the change of the long-range interaction between the polarization in the vicinity of the surface and interface. The free energy expression of thepolarization is described as a function of position of polarization using the Landau phenomenological theory.The simulations of the size effect of the polarization were performed. The simulated result shows that the polarization is stable down to capacitor size of 0.01um2 which can be applied for next generation FeRAM devices.
Pulsed-Laser Deposition of TiNi Shape Memory Alloy Thin Films
Authors: Chen X.Y. , Lu Y.F. , Ren Z.M. , Zhang L. , Wang J.P. , Liew T.Y.F. 
Published: April 2011

ABSTRACTThin films of TiNi shape memory alloy (SMA) have been prepared by pulsed-laser deposition (PLD) at different substrate temperatures. The stoichiometry, crystallinity, and morphology of the deposited films were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and atom force microscopy (AFM). The transformation behavior and crystallization temperatures were investigated by differential scanning calorimetry (DSC). It is found that the Ni content of the deposited films ranges from 46.7 to 52.0 at.%. The crystallization temperature of the amorphous films is around 460°C. The activation energy of the crystallization process is determined by Kissinger's method to be 301 kJ/mol. The martensitic transformation temperature of the annealed Ti-51.5 at.% Ni film is –20.8°C.
Correlations between island nucleation and grain growth for polycrystalline films
Authors: Eisenmenger-Sittner C. , Bergauer A. 
Published: April 2011

ABSTRACTFor Physical Vapor Deposition (PVD) processes the nucleation and growth of stable islands on monocrystalline and even polycrystalline substrates can be described by the rate equation theory in a mean field approximation. The observable quantity which can be derived from the rate equations is the global density of stable islands. Interisland correlations and island size distributions, on the other hand, cannot be obtained from this formalism. The array of stable islands, in turn, forms the template for the subsequent growth of a polycrystalline thin film. For the initial grain shape and grain size therefore both, the global island density as well as possible interisland correlations play a key role.This paper presents the results of simulations which take into account the effects of both, the global island density as well as island/island correlations on the growth of a thick polycrystalline film. The simulations consist of two steps: first a polycrystalline template is generated from an initial distribution of stable islands by employing an algorithm for the construction of Voronoi-zones. The Voronoi zone network mimics the state of the film just after island coalescence and just before the onset of grain growth. Then the well known q-state Potts model of grain growth is employed to study the further steps of microstructural evolution.A higher initial island density leads to a faster onset of grain growth while a very homogenous distribution of islands significantly retards grain growth. The reasons for these effects are briefly discussed.
Formation Mechanism of Silica/Diblock Mesophases by Solvent Evaporation-Induced Self-Assembly
Authors: Yu Kui , Drewien Celeste A. , Hurd Alan J. , Brinker C. Jeffrey , Eisenberg Adi 
Published: April 2011

ABSTRACTIntermediate structures were trapped during the mesophase transition from lamellae to higher curvature structures in a sol-gel matrix. The target structures included normal hexagonally arranged cylinders and/or normal spheres in a cubic array distributed in a hydrophilic matrix. The present system is believed to be the first to trap these intermediates. Through solvent evaporation-induced self-assembly (EISA), mesostructured silica/diblock films with large characteristic length scales were prepared. The structure-directing agents were polystyrene-block-poly(ethylene oxide) (PS-b-PEO) diblock copolymers with high molecular weight, which are water insoluble and alcohol insoluble. We believe that no micellization took place in the present system; a disorder-to-order transition occurred due to the cooperative self- assembly of the diblock and silicates as the solvent preferentially evaporated from a film cast from a dilute homogeneous solution. During further preferential evaporation, the morphogenic effect of the increase of species concentration facilitates the mesophase development in the direction of a normal cubic to hexagonal to lamellar pathway. However, the morphogenic effects of both the decrease of the PS coil dimension and the siloxane condensation drive the mesophase development in opposite directions. The decrease of the PS coil dimension plays an important role in the present self-assembly process. Trapping of the intermediates and coexisting multiple mesophases are related to the facts that PS has high Tg and high hydrophobicity in particular, as well as to the fact that polymers have relatively low mobility in general.
Characterization of chemical and sensoric properties of ion-beam modified polyethersulfone layers
Authors: Sahre Karin , Eichhorn Klaus-Jochen , Simon Frank , Guenther Margaritha , Suchaneck Gunnar , Gerlach Gerald 
Published: April 2011

ABSTRACTThin polyethersulfone (PES) films were irradiated with boron ions at doses between 1013-1016B+/cm2 and energies of 50, 130 and 180 keV. The induced changes of structural and optical properties were studied in detail. The influence on sensoric properties (moisture uptake, conductivity) was also in the focus of interest. The results of vibrational spectroscopy and X-ray photoelectron spectroscopy (XPS) indicate that in dependence on dose and energy of implanted boron ions the sulfone bonds are destroyed, and carbon-rich, amorphous and graphite-like structures are formed. This structural changes cause an increase of the conductivity of the surface films to a value of 10−8 Ω−1 at a dose of 1016 B+/cm2 from an as- prepared value of 10−15 Ω −1 and an increase of the saturation concentration during the moisture uptake.