bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis, Properties and Applications of Superhard Amorphous Coatings
Authors: Tamor Michael A. 
Published: April 2011

ABSTRACTLow-friction/ultralow-wear coatings allow “surface engineering” for improved performance and durability, and enable use of new light weight or low cost materials. The accepted correlation of wear resistance with hardness suggests use of ceramic carbides and nitrides, with diamond being the ultimate anti-wear coating. While any of these may be deposited by chemical vapor deposition, the high cost (due to low deposition rates and high capital costs) and (usually) high deposition temperatures makes CVD coating impractical for cost-sensitive automotive applications. While rarely as hard as their crystalline counterparts, hard amorphous films exhibit similar (and occasionally superior) tribological properties and may be deposited on virtually any material at low cost. The highly nonequilibrium deposition process - conformal plasma reactive ion plating (CP-RIP) - allows tailoring of film properties and exploration of completely new compositions with no crystalline counterparts. Factors controlling the mechanical and optical properties of amorphous hard coatings, and recent progress in their application will be reviewed.
Stability, Chemical Bonding and Vibrational Properties of Amorphous Carbon at Different Mass Density
Authors: Köhler Th. , Frauenheim Th. , Jungnickel G. 
Published: April 2011

ABSTRACTWe describe correlations between the atomic-scale structure and the global electronic and vibrational properties in amorphous carbon versus mass density. The model structures have been generated by applying different annealing regimes using a density-functional based molecular-dynamics (DF-MD) method. The stability of the amorphous modifications and the calculated vibrational density of states (VDOS) are strongly affected by the density and the annealing sequences, altering the chemical composition, the sp/sp2/sp3-clustering, the structure and related physical properties. A mass density of 3.0 g/cm3 is confirmed as a magic density favoring the formation of most stable a-C modifications having lowest defect densities and maximum band gap. In analyzing the vibrational spectra and the localization of modes in comparison with crystalline diamond and graphite, we identify the spectral signatures for chemically different bonded species and defects, that may be used for comparison with related Neutron-, Raman- and IR- work.
Relationship of Processing Conditions to Growth Rate and Quality of Diamond Grown by Chemical Vapor Deposition
Authors: Angus John C. , Cassidy William D. , Wang Long , Wang Yaxin , Evans Edward , Kovach Christopher S. , Tamor Michael A. 
Published: April 2011

ABSTRACTDiamond quality is strongly coupled to growth rate. Incorporation of nondiamond (sp2) carbon and morphological instabilities both increase with increasing growth rates. The intersection of twins with the growth surface produces re-entrant corners that enhance growth in the plane of the twin. Morphology and the development of texture both depend on substrate temperature and methane concentration and hence on growth rate. Experimental evidence and modeling results that relate growth rates and quality to controllable process parameters are reviewed.
High-Temperature Indentation of Natural Diamond and the Quest for Lonsdaleite
Authors: Pirouz P. , Garg A. , Ning X. J. , Yang J. W. , Xiao S. Q. 
Published: April 2011

ABSTRACTAttempts were made to produce bands of hexagonal diamond (Lonsdaleite) by high-temperature indentation of cubic diamond. (011) wafers of type I diamond were indented over the temperature range 1000–1300°C and the microstructure of the indentation plastic zone investigated by transmission electron microscopy (TEM). No hexagonal diamond was produced; instead, the plastic zone consisted of arrays of dislocations lying on the {001} planes. A possible mechanism for the generation of such dislocations, and reasons for the absence of hexagonal diamond, are discussed.
Indentation Characterisation of Carbon Materials
Authors: Field John S. , Swain M. V. 
Published: April 2011

ABSTRACTHigh precision force-displacement measurements of various forms of glassy and graphitic carbon have been made with a Berkovich and spherical tipped indenter. The force-displacement data show almost complete recovery despite contact pressures exceeding a considerable fraction of the elastic modulus. With a spherical tipped indenter the transition from elastic to inelastic response could be readily identified. It was found that the extent of the hysteretic response with a spherical indenter increased with increasing load. Only minor differences in the force-displacement response of crystalline graphite indented normal to the basal plane and the glassy carbon was identified. A simple model for interpreting the force-displacement data is developed. These results are compared with indentations made on diamond like carbon films on various substrates.
The Effects of Collimator Life Time on the Ti and Tin Film Growth Rates and Conformalities in Sputter Deposition Processes: Experiments and Simulations
Authors: Liao Hung , Stippel Hannes , Reddy Krishna , Geha Sam , Brown Kevin , Lindorfer Philipp , Saha Samar , Lin Zhou , Cale Timothy 
Published: April 2011

AbstractExperimental and simulation studies were conducted in an attempt to understand the effects of collimator life time on the Ti and TiN film growth rates and conformalities in sputter deposition processes. The Ti and TiN films were deposited with and without collimation. The hexagonal cells of the collimator used in this study have a 1:1 aspect ratio. A Monte Carlo based simulator was used to calculate the angular distributions of species exiting from a collimator cell and the percentage decrease in the rate of film growth as a function of the collimator life time. Then, a low pressure deposition process simulator, EVOLVE, was used to predict the conformalities of deposited films in contacts or vias, assuming that the films were uniformly deposited on the side-walls of collimator cells. We conclude that the loss in growth rate is largely due to the shrinkage in the cross sectional area of the collimator cell inlets. We arrive at this conclusion after comparing an estimated film thickness on the collimator side-walls with experimental measurements. With extended collimator usage, the predicted and experimental film profiles in contacts or vias show increasing bottom coverage and decreasing side-wall coverages.
Low Temperature (≥ 400°C) Silicon Pyrometry AT 1.1μm with Emissivity Correction
Authors: Sturm J. C. , Reddy A. 
Published: April 2011

AbstractIn this work we have examined the experimental low-temperature limits of 1.1μm pyrometry for the measurement of the temperature of silicon wafers and aluminumcoated silicon wafers at temperatures under 700°C in RTP chambers. In-situ emissivity correction in the same range has also been demonstrated with a single detector for radiation and reflection measurements. Temperatures as low as 450°C have been measured on metallized surfaces with an accuracy of better than 10°C without any a priori knowledge of the wafer emissivity.
Rapid Thermal Processing-Manufacturing Perspective
Authors: Thakur R. P. S. , Schuegraf K. , Fazan P. , Rhodes H. , Zahorik R. 
Published: April 2011

AbstractWhile repeatable and accurate measurement of temperature in rapid thermal processing (RTP) remains a subject of ongoing research, inception of large-diameter wafers and deep subhalf micron design rules may be viewed as good news for implementing RTP during the development phase for later transfer to volume manufacturing. To date, the only well-established application of RTP in manufacturing is silicide annealing. However, research during the past decade has demonstrated the feasibility of using RTP to replace essentially all furnace-based thermal processes in sub-half micron process flows. These developments in the RTP capability offer several technological and economic benefits such as improved defect control, higher product yields, and faster development cycles for DRAM-type technologies at a reduced cost and with an earlier entry of the driver products during the revenue-generating period.In this paper, we review several applications of RTP such as silicide anneals, borophosphosilicate glass (BPSG) reflow, dopant activation, and rapid thermal nitridation (RTN) and discuss the integration issues related to advanced process flows. Furthermore, we highlight important manufacturing parameters like throughput, machine cost and uptime, software and hardware issues, wafer dimensional analysis, and simulation expectations. While considering volume manufacturing, we make some calibration and process control recommendations.
Characterization of Rapid Nitrided Ultrathin SiO2 Films By XPS and SCS
Authors: Yan H. , Wong S. P. , Chan R. W. M. , Kwok R. W. M. , Feng W. X. 
Published: April 2011

AbstractUltrathin SiO2 dielectric layers of thickness less than 100Å on silicon substrates have been prepared by dry oxidation and rapid thermal nitirdation (RTN). In this study, X-ray photoelectron spectroscopy and surface charge spectroscopy had been applied to study the nitrogen distribution in the dielectric layers and the change in the interface state density (Dit) due to the nitrogen incorporation. It is found that most of the incorporated nitrogen is located near the dielectric/Si interface and the nitrogen content increases with the RTN temperature. For the electrical properties, we found that the Dit, after RTN slightly decreases and the breakdown field strength deduced from the dielectric surface potential was enhanced by the incorporation of nitrogen.
Controlled Thin Oxidation and Nitridation in a Single Wafer Cluster Tool
Authors: Sagnes I. , Laviale D , Glowacki F. , Blanchard B. , Martin F. 
Published: April 2011

abstractFor both advanced MOS technologies (gate length ≤ 0.25.μm) and EEPROMs, the quality and reproducibility of thin dielectric films (≤ 6 nm) are essential. To obtain such dielectrics involves very precise control of the silicon surface preparation and gate oxide growth. Furthermore, research into such supplementary properties of oxide as improved SiO2/Si interface resistance to current injections or enhanced p+gate resistance to boron penetration in the channel may require nitridation treatment. Such a sequence of steps can be carried out under controled atmosphere using a cluster tool. This paper presents the preliminary results obtained in a single wafer cluster tool on i) the surface preparation under ozone of a silicon wafer immediately after diluted liquid HF treatment and ii) the nitridation of the 6 nm gate oxide under low temperature, low pressure gaseous NO. It is shown that the NO molecule can be successfully used in Rapid Thermal Processing (RTP) and allows gate oxides to be nitrided with properties at least equivalent to those obtained under N2O nitridation, but with a strikingly reduced thermal budget.
Emissivity Of Rough Silicon Surfaces: Measurement And Calculations
Authors: Xu H. , Sturm J. C. 
Published: April 2011

AbstractThe directional reflectance and approximate emissivity of rough silicon wafers were measured by reflection measurements using a single point detector and a broad area illumination source. Experiments were also performed to determine the cone angle of the incident light required to properly measure the emissivity of rough backsides. Based on surface roughness parameters acquired with an Atomic Force Microscope, reflectance calculations were performed within the framework of the Beckmann-Spizzichino model. The results are qualitatively consistent with experimental observations.
RTA-Preparation of β-FeSi2 Layers from MBE-Grown Fe-Si Films Deposited on Si and Relaxed SiGe (100) Substrates
Authors: LíBezný M. , Poortmans J. , Dekoster J. , Degroote S. , Vantomme A. , De Lange B. G. M. , Langouche G. , Nijs J. 
Published: April 2011

AbstractRapid thermal annealing (RTA) of Fe-Si layers co-deposited on n- and p- type Si (100) and Si-capped relaxed Si0.6Ge0.4 (100) substrates was studied. Relaxed (100) Si0.6Ge0.4 epitaxial layers represent a pseudo-matched substrate for the β-FeSi2 phase. Fe-Si layers with a 1:2 composition ratio were deposited at room temperature in an MBE system. Samples were then subjected to a rapid thermal annealing in a H2/N2-atmosphere in the temperature range between 500 and 800 °C. Conversion electron Mössbauer spectroscopy showed that the layers consist of the β-FeSi2 phase. Nomarski microscopy revealed crystal grains of the diameter from 5 to 10 μm. Cross-section transmission electron microscopy study found smooth surfaces and interfaces. No significant structural defects were found inside the grains. Differences between current-voltage characteristics of simple devices prepared on these layers agree with the trends expected from their band diagrams.
Influence of Oxygen on Rapid Thermal Co-Diffusion of Phosphorus and Aluminium in Silicon
Authors: Mahfoud K. , Hartiti B. , Muller J. C. , Siffert P. 
Published: April 2011

AbstractLocal motion, diffusion and interaction of impurities in solids are important aspects of semiconductor material and device processing. Rapid thermal processing (RTP) is extremely concerned and appears to offer significant advantages in these areas. As oxygen is one of the dominant impurities present in silicon, various applications require different level of oxygen to improve the device performance.In this work, we have taken the advantage of this feature to study the effects of the oxygen concentration in silicon on the rapid thermal co-diffusion of phosphorus and aluminium. In particular, we will show that the large enhancement of the minority carrier diffusion length (LD) due to this process can be related to the presence of oxygen and carbon which influences during the thermal cycle are of importance.
Modeling, Simulation and Control of Single Wafer Process in Cluster Tool Base on Ft-Ir In-Line Sensor
Authors: Liu Shaohua , Solomon Peter , Carpio R. , Fowler B. , Simmons D. , Wang J. , Wise R. , Imper G. , Riley N. B. , Moslehi M. , Ravindra N. M. 
Published: April 2011

AbstractThis paper outlines our current approach to utilize infrared reflectance spectroscopy for thin film measurement in the semiconductor industry. The multi-layer thickness and doping concentration of IC wafers can be determined by a single angle, unpolarized infrared reflectance measurement performed using Fourier transform infrared spectrometer. A computer algorithm, which matches theoretical tc measured infrared reflectance spectra, was successfully employed to determine multiple thin film properties.
Density-Functional Based MD Studies of Low-Energy Atom Collisions onto Diamond and Graphite
Authors: Uhlmann S. , Stephan U. , Frauenheim Th. , Seifert G. 
Published: April 2011

ABSTRACTThe near-surface implantation of hyperthermal neutral atoms with (15 - 75) eV onto diamond (111) and graphite substrates is studied by molecular-dynamics (MD) using a density-functional (DF) based non-orthogonal tight-binding (TB) scheme. Depending on the initial energy and the impact point the atoms penetrate beneath the surface forming regions of local disorder and stress. The energy partition during the collision is analyzed yielding results about penetration and displacement threshold. After a final relaxation of the structures the penetration depths of the colliding particles are determined. The structural topology and the electronic properties of the induced defects and surface modifications are discussed. The penetration thresholds for noble gas atoms, hydrogen and carbon and the atomic-size dependent bulge arising after the subplantation process into a graphite substrate have been determined.
Evaluation of Anisotropic Film Structure of Amorphous Alloy by Computer Simulation
Authors: SATO A. , YAMAMOTO H. 
Published: April 2011

ABSTRACTA film growth of a virtual GdCo amorphous binary alloy was studied with a molecular dynamics simulation. A deviation of the atomic environment δ and an atomic pair distribution index η were calculated to evaluate the atomic structure of the prepared film. It was found that an anisotropic atomic distribution is induced in the film. The value of δ for a Gd atom environment is of the order of 10−4 and is almost in quantitatively agreement with the experimental value. The anelastic deformation is affected by the roughness of the substrate and becomes large in the film deposited on a smooth substrate. The value of η shows that the atomic pairs preferentially orient toward a horizontal film plane. The obtained results strongly support a single ion model as a main origin of a perpendicular magnetic anisotropy experimentally observed in amorphous rare earth-transition metal alloy films.
Parameters for Feature Evolution Models in Plasma Etching from Molecular Dynamics Simulation
Authors: Helmer B.A. , Graves D. B. , Barone M.E. 
Published: April 2011

ABSTRACTThe impact of Si with incident energy Ei (0.1, 1, 5, 10, 20, and 50 eV) and angle θi (0° and 60° from the surface normal) into three model Si surfaces with varying degrees of F coverage (0 ML F, ∼ 1 ML F, and ∼2 ML F) was simulated using classical molecular dynamics (MD). From the simulation results, the probabilities for incident Si reflection and removal of surface Si and F were obtained as a function of Ei, θi, and F surface coverage. In general, these probabilities were observed to depend significantly on these parameters. This result implies that feature evolution simulations require surface reaction models with the necessary functionality in order to make quantitative predictions.
Characterization of Quantum Heterostructures. A Simulation Method Combining the Evaluation of Lattice and Electrons Configuration and TEM Imaging.
Authors: Mattei G. , Mazzone A. M. 
Published: April 2011

ABSTRACTThis work analyzes the characterization of the structural properties of quantum heterostructures by HREM. A simulation of atomistic type is used to construct a Fe/Ag bilayer few nm thick and the HREM image of this structure is calculated by using a standard dynamical diffraction method. The comparison of the two calculations indicates that the interfacial disorder spans few layers and can be resolved against the background of two well-registered lattices.
The Potential Effect of Multilayer Patterns on Temperature Uniformity During Rapid Thermal Processing
Authors: Hebb Jeffrey P. , Jensen Klavs F. , Egan Erik W. 
Published: April 2011

ABSTRACTThis work aims to systematically gain an understanding of the effects of multilayer patterns on wafer temperature uniformity during rapid thermal processing, and explore possible solutions to the problem. Steady state and transient wafer temperature distributions are simulated by combining a detailed reactor transport model with multilayer electromagnetic theory to predict wafer radiative properties. A generic axisymmetric RTP system with single-side illumination is used as a testbed to explore pattern effects for a simulated source/drain implant anneal.
An Analytic Approach to the Radiation Fields of Tubular Halogen Lamp Arrangements in RTP Reactor Blocks
Authors: Theiler Thomas 
Published: April 2011

ABSTRACTStarting with basic physical radiation principles and with Beers law formulas for the radiation characteristics of arrays of pointlike radiation sources and tubular halogen lamps are analytically derived. Different arrangements of tubular halogen lamps are considered and compared with each other. Homogeneity criteria are worked out and it is demonstrated that the minimum homogeneity distance between a plane in which all filaments are arranged parallel to each other, and an object depends only on the distance between two neighbouring filaments and thus can be given by a simple number. Interesting aspects for RTP equipment manufacturers as well as for users are demonstrated by comparing different lamp arrangements with each other: In crossed lamp fields latticelike inhomogeneity knots arise in the object plane at points where the lamp filaments of the upper and the lower lamp plane cross. If the filaments are arranged parallel to each other in two filament planes, very homogeneous results are obtained when the filaments of the two planes interlace.
Silicon AD-Dimer Binding on Si(100)
Authors: Bedrossian Peter J. , Smith Arthur P. , Jonsson Hannes 
Published: April 2011

ABSTRACTIsolated Si ad-dimers nucleate predominantly on Si(100) substrate dimer rows at room temperature. Using tunneling microscopy (STM), we find that, while ad-dimers oscillate between two mutually orthogonal orientations, the geometry with the ad-dimer bond perpendicular to the substrate's dimer bonds is the more stable. This observation confirms a prediction of ab initio calculations with a gradient correction for the energies of ad-dimers in various configurations, which differs from that of the local density approximation (LDA).
Simulation of Multicomponent Thin Film Deposition and Growth
Authors: Burmester C. P. , Wille L. T. , Gronsky R. 
Published: April 2011

ABSTRACTResults from a multicomponent Monte Carlo simulation of the deposition and growth of YBa2Cu3O7 are presented and discussed. In particular, a detailed examination of the growth modes active during different morphological growth conditions is performed. At higher deposition rates, both [001] and [100] epitaxial variants (‘c’ and ‘a’ type growth, respectively) are observed to grow by modes attributed to the classic Volmer-Weber mechanism. At very low deposition rates, the film is observed to grow in a distinct, cyclic, multi-stage process. Small islands of [001] epitaxy nucleate and grow to one unit cell height followed by primarily horizontal growth or “ledge extension” until one unit cell layer has formed. This process then repeats. Simulated RHEED amplitude data from this growth process compares favorably to experimentally obtained data.
Hot Carrier Degradation of Gain in Bipolar Transistors
Authors: Kizilyalli Isik C. , Bude Jeff D. 
Published: April 2011

AbstractIn this paper hot carrier related aging of n-p-n bipolar transistors is investigated experimentally and theoretically to bring physical insight into the bipolar transistor hFE (common emitter current gain) degradation. Electrical stress experiments are performed on transistors with different base doping profiles at varying temperatures. Detailed process simulations are performed to determine the doping profiles of the base-emitter junction. Monte Carlo transport simulations are then performed at different temperatures and bias conditions to determine the electron and hole distribution functions in the baseemitter junction. AT&T's 0.8 μ.m BICMOS technology is used to fabricate the experimental bipolar transistor structures. For this non-self aligned technology we attribute hFE degradation to the presence of hot holes and secondary electrons which are generated by hot hole impact ionization. This feed-back due to impact ionization has a dominant effect on the high energy tails of the distribution of both holes and electrons even when the overall current multiplication is low. Simple hot electron energy transport models do not contain the complexity to properly describe ionization feedback and carrier heating, and are therefore inadequate. An exponential dependence of the transistor lifetime on BVEBO is deduced for constant voltage stress (Vstress < BVEBO) conditions, confirming the importance of secondaries in the process of degradation.