bluuebunny/crossref_metadata_2025_split huggingface dataset:
Atomistic simulations of extrinsic defects evolution and transient enhanced diffusion in silicon
Authors: Claverie A. , Colombeau B. , Cristiano F. , Altibelli A. , Bonafos C. 
Published: April 2011

ABSTRACTWe have implemented an atomistic simulation of the Ostwald ripening of extrinsic defects (clusters, {113}'s and dislocation loops) which occurs during annealing of ion implanted silicon. Our model describes the concomitant time evolution of the defects and of the supersaturation of Si interstitial atoms in the region. It accounts for the capture and emission of these interstitials to and from extrinsic defects (defined by their formation energy) of sizes up to thousands of atoms and includes a loss term due to the interstitial flux to the surface. This model reproduces well the dissolution of {113} defects in Si implanted wafers. We have subsequently studied the characteristics of TED in the case of B implantation at low and ultra low energy. In such cases, the distance between the defect layer and the surface plays a crucial role in determining the TED decay time. The simulations show that defect dissolution occurs earlier and for smaller sizes in the ultra-low energy regime. Under such conditions, TED is mostly characterized by its “pulse” component which takes place at the very beginning of the anneal, probably during the ramping up. In summary, we have shown that the physical modelling of the formation and of the growth of extrinsic defects leads to a correct prediction of the “source term” of Si interstitials and at the origin of TED.
An Evaluation on The Effects of Newly Designed Abrasives in CMP Slurry
Authors: Kawahashi Nobuo , Hattori Masayuki 
Published: April 2011

ABSTRACTNewly designed abrasives with various particle morphology and component have been prepared and evaluated in terms of polish efficiency for CMP application. Polymer sphere with uniformed particle size and special functional group were prepared by soap-free emulsion polymerization. CMP slurry including polymer abrasives indicated characteristic properties such as dishing, erosion and low defectivity for metal and dielectric surface. This study has been also conducted on the preparation of composite particles consisting of polymer core covered with inorganic composition such as zirconium compound, titanium compound, SiO2 and Al2O3. The controlled hydrolysis and heterocoagulation systems were proposed as preparation methods of composite particles. 1st step Cu-CMP Slurry with composite particles as abrasion indicated an excellent dishing, erosion and their over-polish-margin. Particularly these composite particles were useful to prevent increasing scratch on the TEOS and low-k dielectric materials surface in 2nd step CMP process.
Copper CMP for Dual Damascene Technology: Some Considerations on the Mechanism of Cu Removal
Authors: Wei David , Gotkis Yehiel , Li Hugh , Jew Stephen , Li Joseph , Srivatsan Sri , Simon Joseph , Boyd John M. , Ramanujam KY , Kistler Rodney 
Published: April 2011

ABSTRACTIt was found in a Cu-CMP process using EP-C 5001 slurry and IC 1000 pad that Cu removal rate, being extremely low without H2O2 in the slurry, increases up to a maximum with the addition of H2O2, and then decreases again. Analysis of polarization curves and Eh-pH diagrams shows that without H2O2 Cu has the lowest electric potential, as a result, the highest thermodynamic stability in the Cu/slurry system. Addition of H2O2 shifts the potential up and induces the formation of Cu2O, resulting in a high removal rate. At high H2O2 concentration, a CuO passivation film is formed. In this case, only mechanical removal of the passivating oxide film allows the process to proceed. It is speculated that the moving pad surface adheres the oxidized species via the formation of hydrogen bonds with oxygen atoms of copper oxide molecules, thus detaching them from the wafer surface. Each oxygen atom is capable of pulling out two Cu atoms if Cu2O is formed on the surface and only one Cu atom if CuO is formed. This would explain why the removal rate is high at low H2O2 concentration and low at high H2O2 concentration.
A Study on STI and Damascene CMP using Chip Level Simulation
Authors: Kim Kyung-Hyun , Kim Yoo-Hyon , Kim Kwang-Bok , Hong Chang-Ki , Yoo Moon-Hyun 
Published: April 2011

ABSTRACTSimulation of chemical-mechanical polishing is important because the chip-level planarity are difficult to control. The simulator has been developed for predicting and optimizing the thickness distribution after the STI and damascene CMP as well as ILD CMP using chip-level pattern density, elastic spring model and erosion model. In this study, the results of CMP simulation is shown to agree well with the measured data. The simulator can be used to optimize CMP process conditions and to generate design rules for filling dummy patterns which are used to improve the planarity and uniformity.
Slurry Retention and Transport during Chemical-Mechanical Polishing of Copper
Authors: Jindal Anurag , Li Ying , Narayanan Satish , Babu S. V. 
Published: April 2011

ABSTRACTThis work investigates the retention and transport of chemical species and abrasive particles during chemical-mechanical polishing (CMP) of copper (Cu). “Slurry step-flow” experiments, in which the concentrations of the chemicals and abrasives in the slurry are altered in steps during polishing were conducted with hydrogen peroxide (H2O2)/glycine based slurries. Two different pads, Suba-500 and IC 1400 (with k grooves), were compared in terms of their slurry retention and transport characteristics. With these experiments, it has been shown that both the abrasives and chemicals are constantly replaced during a typical CMP process. Better polishing performance of the IC 1400 over Suba 500 is a result of improved transport of the chemicals and the abrasives between the wafer/pad interface.
Modeling of Pattern Dependencies for Multi-Level Copper Chemical-Mechanical Polishing Processes
Authors: Tugbawa Tamba , Park Tae , Lee Brian , Boning Duane 
Published: April 2011

ABSTRACTWepropose an integratedcontact mechanics and density-step-heightmodel of pattern dependencies for the chemical-mechanical polishing (CMP) of multi-level copper interconnects, and show preliminary comparisons with experimental data for the overburden copper removal stage. The model uses contact mechanics to correctly apportion polishing pressure on all sections of an envelop function that reflects the long-range thickness differences on the chip, or region of interest. With the pressure over the entire envelop known, the density-step-height part of the model is then used to compute the amount of material removed in the local “up-areas” and “down-areas”. ThismodelshowspromiseinaccuratelyandefficientlypredictingpostCMPcopperanddielectric thicknesses across an entire chip.
A Contact-Mechanics Based Model for Dishing and Erosion in Chemical-Mechanical Polishing
Authors: Vlassak Joost J. 
Published: April 2011

ABSTRACTWe present a new model for dishing and erosion during chemical-mechanical planarization. According to this model, dishing and erosion is controlled by the local pressure distribution between features on the wafer and the polishing pad. The model uses a contact mechanics analysis based on the work by Greenwood to evaluate the pressure distribution taking into account the compliance of the pad as well as its roughness. Using the model, the effects of pattern density, line width, applied down-force, selectivity, pad properties, etc. on both dishing and erosion can be readily evaluated. The model may be applied to CMP used for oxide planarization, metal damascene or shallow trench isolation.The model is implemented as an algorithm that quickly calculates the evolution of the profile of a set of features on the wafer during the polishing process. With proper calibration of the process parameters, it can be used as a tool in optimizing the CMP process and implementing CMP design rules.
A CMP Numerical Model Combining Die Scale and Feature Scale Polishing Characteristics
Authors: Delage Stéphanie , Meyer Frank , Springer Goetz 
Published: April 2011

ABSTRACTIn this paper a new numerical model combining die scale and feature scale polishing characteristics for oxide CMP is proposed. This work is based on the effective density model [1-3] which takes into account a die scale pad deformation. We have extended this model to include the description of material removal at the feature scale. A pseudo topography discretization allows us to describe the polishing in down areas more accurately depending on the down area width. The physical parameters considered include the deformation of the polishing pad (die scale and feature scale), the removal rate of a blanket wafer polished under the same process conditions, and the removal rate in down areas for small polishing times.Comparison of simulated results with MIT testreticle experiments has been performed and evaluated.
Control of Pattern Specific Corrosion During Aluminum Chemical Mechanical Polishing
Authors: Kim Hyungjun , Kwon Panki , Lee Sukjae , Kim Hyung-Hwan , Lee Sang-Ick , Song Seo-Young , Nam Chul-Woo 
Published: April 2011

ABSTRACTA pattern specific corrosion of aluminum wires was found during aluminum chemical mechanical polishing process. This paper presents and discusses the particular pattern dependency of the corrosion behavior and effective control methods in order to reduce the corrosion. An aluminum single damascene structure on silicon dioxide thin film was prepared and the effects of process variables and pattern configuration on corrosion behavior were extensively explored. The corrosion behavior was quantitatively analyzed using sheet resistance of corroded line. It was demonstrated that corrosion of aluminum wire was associated with cleaning media and pattern configuration. The area ratio between sub-micron size line and pads was the most important factors to determine the corrosion behavior. A post cleaning chemical including corrosion inhibitor couldn't prevent the corrosion perfectly. It was found that sacrificial dummy lines could reduce the aluminum corrosion, which suggests that the aluminum corrosion could be controlled by the structural consideration in aluminum damascene.
Heteroepitaxial growth of TaN on MgO(001) and TiN(001)/Si(001) by pulsed laser deposition
Authors: Cheung H. Y. , Wong K.H. 
Published: April 2011

ABSTRACTEpitaxial TaN(001) films have been successfully grown on MgO(001) single crystal and TiN(001) buffered Si(001) substrates by pulsed laser deposition method. Crystalline TaN layers of about 100 nm thick were deposited under a base pressure of 5 × 10−6 Torr and at substrate temperatures ranging from 500°C to 700°C. X-ray diffraction results suggested that stoichiometric TaN films with cube-on-cube <001>TaN∥<001>MgO heteroepitaxy are obtained in this temperature range. Plan-view and cross-sectional electron microscopy analysis revealed excellent structural quality and sharp interface boundary. TaN films grown on TiN(001) buffered Si(001), however, showed a mixture of TaNx (with x ≤ 1) components. Although the (001)-orientated TaN is always present prominently, the nitrogen deficient TaNx components are often co-existed in the films and show up as a broad peak in the X-ray diffraction profile. Stoichiometric and single phase TaN(001) films can only be obtained in a narrow temperature window at around 550oC and heteroepitaxial relation <001>TaN∥<001>TiN∥<001>Si has been demonstrated.
Vacancies in Homoepitaxially-Grown Ag and Cu films
Authors: Botez Cristian E. , Elliott William C. , Miceli Paul F. , Stephens Peter W. 
Published: April 2011

ABSTRACTX-ray scattering experiments on the homoepitaxial growth of Ag(001) Ag(111) and Cu(001) show that high vacancy concentrations can be achieved during low temperature deposition. It is observed that the vacancies, which can attain concentrations on the order of 2%, extend throughout the thickness of the deposited film. Moreover, vacancies are found to have a profound effect on the evolving morphology of certain surfaces, which is discussed in terms of prior studies of kinetic roughening in these systems.
Dislocation Arrays in the Interfaces between Substrates and Epitaxial Islands
Authors: Lakshmanan Annamalai , Gopal Vidyut , King Alexander H. , Kvam Eric P. 
Published: April 2011

ABSTRACTWe present a model for dislocation array image effects during epilayer island growth. Misfit dislocations often appear at an interface between phases, to accommodate a lattice mismatch. In many situations, such as early film growth, one of the phases may be discontinuous, leaving the interface region clearly bounded. The structure of such a finite interface differs from the normally-modeled infinite boundary because of end effects near the edges of the islands. We have modeled the dislocation structure of such a finite interface in MBE-grown InAs islands on GaP, and compare our results to high-resolution images of the same structure. The 11% misfit causes dislocation introduction from the outset of growth. Islands containing between 4 and 14 dislocations were examined, and dislocation spacings were found to be enlarged near the island perimeters. The model provides a clear understanding of this and other effects.
“Magic” Nanostructures During the Early Stage of Thin Film Growth
Authors: Zhang M. , Efremov M. Yu. , Schiettekatte F. , Olson E. A. , Allen L. H. 
Published: April 2011

ABSTRACTThe behaviors of thin indium films in the early stage of growth are studied in situ by a novel ultra-sensitive thin film scanning calorimetry technique. The films consist of ensembles of self-assembled indium nanostructures whose melting temperatures are strongly influenced by size. We experimentally determine the relationship between a nanostructure's radius and its melting point by combining the measured caloric results with nanostructure size distributions obtained from TEM. The results show a linear melting point depression. Moreover, by looking at the fine structures of these caloric curves, we found the discrete nature of nanostructures during the early stage of thin film growth. The measured heat capacity values show several local maxima at certain temperatures. This suggests that preferred energy states exist among these supported nanostructures on amorphous surfaces. These local maxima are related to each other by increments of one monolayer of indium atoms. These findings could be extended from the magic numbers observed previously in cluster beams studies.
Electron Beam - Directed Vapor Deposition of Multifunctional Structures
Authors: Queheillalt D. T. , Katsumi Y. , Wadley H. N. G. 
Published: April 2011

ABSTRACTMultifunctional structures are those that combine load bearing support in addition to supplemental functions such as actuation, electrochemical energy storage or thermal management. Electron beam - directed vapor deposition (EB- DVD) technology has been used for the deposition of templated cellular structures for micro heat-pipe structures and porous electrode coatings for rechargeable nickel - metal hydride cells. In addition to load bearing support, the tem- plated cellular structures exhibit enhanced thermal management characteristics and the electrochemical cells can be integrated into the load bearing supports of linear and truss based structures leading to their multifunctionality. Dur- ing EB-DVD, the electron beam evaporated vapor flux is encompassed by a rarefied transonic inert gas jet, entraining the vapor in a non-reactive gas flow and transporting it onto a polymer or metal template structure. Here, EB-DVD technology has been used to synthesize copper based templated cellular structures for thermal management systems and porous nickel coatings for the positive electrode of rechargeable nickel - metal hydride cells.
The Improvement of Thin Polymer Film Properties Through Plasma Immersion Ion Implantation and Deposition Technique
Authors: Rangel Elidiane C. , Cruz Nilson C. , Mota Rogério P. , Algatti Maurício A. , Honda Roberto Y. , Kuranaga Carlos , da Marcos D. 
Published: April 2011

ABSTRACTThin polymer films were deposited from acetylene and argon mixtures by plasma immersion ion implantation and deposition. The effect of the pulse frequency, ∨, on molecular structure, optical gap, contact angle and hardness of the films was investigated. It was observed progressive dehydrogenation of the samples and increment in the concentration of unsaturated carbon bonds as the pulse frequency was increased. Film hardness and contact angle increased and optical gap decreased with ∨. These results are interpreted in terms of the chain unsaturation and crosslinking.
Remote Plasma Enhanced Chemical Vapor Deposition of TiOx Films from Titanium Tetraisopropoxide
Authors: Nakamura Masatoshi , Kato Shinichi , Aoki Toru , Hatanaka Yoshinori 
Published: April 2011

ABSTRACTTiOx thin films were prepared from titanium tetraisopropoxide (Ti-(O-i-C3H7)4, TTIP) in a remote plasma enhanced chemical vapor deposition (RPE-CVD) using a mixture of hydrogen/oxygen plasma gas. Emission spectra suggested that H-radicals dissociated TTIP molecules in gas phase. By mixing with oxygen, H-radical density was increased with the correlation effect to result in enhancement of deposition rate. Deposition rate was also influenced by OH-radicals. OH-radicals caused deactivation of precursors and hence suppressed Ti-O-Ti bond formation in gas phase. The highest deposition rate of 11 nm/min, which was two orders higher than that for the case of single gas plasma, was achieved in the case of mixture gas ratio of 20% oxygen and 80% hydrogen. Surface reaction due to the heated substrate did not affect the deposition rate though the film structure was remarkably changed. It was demonstrated that for RPE-CVD process, oxygen/hydrogen mixture gas plasma was effective for obtaining high deposition rate, and also H-to-OH radical density ratio was an important factor to control the deposition rate.
Growth and Characterization of Semicontinuous Metal Films by Pulsed Laser Ablation
Authors: So S.K. , Fong H.H. , Cheung N.H. 
Published: April 2011

ABSTRACTSemicontinuous metals films of copper and gold were grown on different substrates by pulsed laser ablation. The resistance and transmittance of these growing metal films were monitored in situ vs film thickness. Despite diverse experimental variations, it was found that both resistance and transmittance exhibited similar behaviors. Around percolation, the resistance exhibited a sharp drop whereas the transmittance exhibited a dip. In general, the onset of percolation depended on laser fluence and substrates. Under favorable conditions, metal films as thin as 1.5 nm would percolate.
STM investigation of energetic insertion during direct ion deposition
Authors: Pomeroy Joshua M. , Couture Aaron , Jacobsen Joachim , Cooper Barbara H. , Sethna J.P. , Brock Joel D. 
Published: April 2011

ABSTRACTThin copper films have been deposited on single crystal copper substrates and characterized using a UHV Scanning Tunneling Microscope to probe the effect of atomic insertions during hyperthermal ion deposition. At low temperatures, atomic insertions are predicted to provide a net downhill current that offsets the roughening effect due to uphill “Schwoebel” currents leading to a net smoothing of the surface. Films have been grown at several different energies targeted to observe a crossover from insertion driven smoothing to adatom-vacancy dominated roughening. Copper thin films are deposited near 20 eV using a mass selected ion deposition system that allows precise control (+/− 2 eV) over the energy of constituent atoms. Experimental observations are compared with a sophisticated Kinetic Monte Carlo and Molecular Dynamics hybrid (KMC-MD) simulation.
Deposition of Ru Thin Films by MOCVD Using Direct Liquid Injection System
Authors: Kang Sang Y. , Hwang Cheol S. , Kim Hyeong J. 
Published: April 2011

ABSTRACTRu thin films were deposited on SiO2/Si and (Ba,Sr)TiO3 [BST]/Pt/TiO2/SiO2/Si substrates using Ru(C2H5C5H4)2 [Ru(EtCp)2] by metal-organic chemical vapor deposition (MOCVD). To determine the effects of the solvent, C4H8O [tetrahydrofuran: THF], it was injected into the reaction chamber by the Direct Liquid Injection (DLI) system while Ru(EtCp)2 was input through the bubbler system. Also, Ru thin films were deposited using a liquid source, Ru(EtCp)2 dissolved in THF, delivered by the DLI system. The surface of the Ru thin films deposited on the BST substrate using only Ru(EtCp)2 through the bubbler system was very rough and milky, but the addition of THF made the surface of the films smooth and clean. In addition, Ru films deposited at 325°C using Ru(EtCp)2 dissolved in THF through the DLI system have a dense and smooth microstructure with resistivity as low as 15µωcm.
The Laser-Mössbauer Method for Surface Evolution and Thin Film Microstructure
Authors: Sorescu Monica 
Published: April 2011

ABSTRACTUsing amorphous Fe81B13.5Si3.5C2, Fe40Ni38Mo4B18, Fe66Co18B15Si1 and Fe72.6Cr22Al4.8Si0.3Y0.3 as model systems, we apply the laser-Mössbauer method in order to obtain metallic glasses with novel properties. As shown by transmission Mössbauer spectroscopy, the bulk magnetic texture was modified in a rational manner by applying a varying number of excimer laser pulses per spot (λ=248 nm, τ=8 ns). As shown by conversion electron Mössbauer spectroscopy, this process left the surface magnetic texture unchanged and induced a distribution of magnetic moment directions throughout the thickness of the foil. A similar dependence of the magnetic texture upon the number of applied laser pulses was obtained in metallic glasses irradiated with a Nd:YAG laser (λ=532 nm, τ=8 ns). However, in this case we observed the onset of surface crystallization in the hyperfine magnetic field distributions extracted from the CEMS spectra. When a pulsed alexandrite laser was used (λ=750 nm, τ=60 μs), the onset of crystallization was found to be accompanied by bulk oxidation and the formation of magnetite particles in the irradiated system. Finally, a crucial experiment was performed in order to demonstrate the role played by the magnetostriction constant in the onset of crystallization.
Epitaxial NiO-Co exchange-biased bilayers grown on MgO single crystals Influence of the substrate orientation on the film morphology, the Co structure and the magnetic behavior
Authors: Warot B. , Snoeck E. , Ousset J.C. , Casanove M.J. , Dubourg S. , Fert A.R. , Bobo J.F. 
Published: April 2011

ABSTRACTCo/NiO bilayers have been grown on MgO(001), MgO(110) and MgO(111) substrates in an ultra high vacuum sputtering chamber. Growth mode and surface morphology are investigated by X-ray diffraction, Reflection High Energy Electron Diffraction (RHEED), Atomic Force Microscopy (AFM) and High Resolution Transmission Electron Microscopy (HRTEM). NiO layers grow epitaxially whatever the substrate orientation. Flat surfaces are observed on NiO/MgO(001) whereas on MgO(110) the NiO surface exhibits a roof-like morphology consisting in (100) and (010) facets elongated along the [001] direction. On MgO(111), the NiO surface presents pyramids with {100} facets. A temperature dependence of the cobalt layer structure is observed: on NiO(001) at room temperature it grows in its high temperature face-centered cubic structure (fcc), whereas it has the hexagonal close-packed structure (hcp) when deposited at slightly higher temperatures.