bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Application of Solid Source Diffusion in the Vertical Replacement-Gate (VRG) MOSFET
Authors: Oh Sang-Hyun , Hergenrother J.M. , Monroe Don , Nigam T. , Klemens F.P. , Kornblit A. , Mansfield W.M. , Baumann F.H. , Gossmann H.J. , King C.A. , Kleiman R.N. , Vuong H-H. , Weber G.R. , Rafferty C.S. 
Published: April 2011

AbstractWe discuss the first use of solid source diffusion (SSD) to form shallow, self-aligned SDEs in a novel device known as the Vertical Replacement-Gate (VRG) MOSFET. This is the only MOSFET ever built that combines 1) a gate length controlled precisely through a deposited film thickness, independently of lithography and etch, and 2) a high-quality gate oxide grown on a single-crystal Si channel. The use of SSD in this novel geometry allows us to transform the precise gate length control afforded by the VRG process into precise, lithography-independent channel length control. In the VRG-nMOS process, silicon nitride offset spacers separate the phosphosilicate glass (PSG) SSD dopant sources from the polysilicon gate. These offset spacers, whose critical dimensions are also controlled by film thicknesses, allow us to precisely tune the gate-source and gate-drain overlaps in order to optimize the capacitance/series resistance tradeoff. These parasitic overlap capacitances have precluded the high-frequency operation of many previous vertical MOSFETs. In this paper, we discuss the SIMS and sheet resistance characterization of shallow phosphorus junctions formed in one-dimensional SSD experiments. We will also discuss the scanning capacitance characterization of two-dimensional doping profiles of VRG-nMOSFETs with gate lengths down to 50 nm.
Low Energy Implantation of Boron with Decaborane Ions
Authors: Albano Maria A. , Babaram Vijay , Poate John M. , Sosnowski Marek , Jacobson Dale C. 
Published: April 2011

AbstractFormation of p-type shallow junctions for future generations of Si devices will require ion implantation of B at very low energies (< 1 keV). An alternative to implantation of monomer ions at very low energy is implantation of large molecular ions at a higher energy. In an ion beam of decaborane (B10H14) each of the B atoms carries only 9% of the ion kinetic energy. We have examined ionization properties of decaborane and built an experimental ion source and an implantation apparatus with magnetic mass analysis. Analyzed decaborane ion beams with energies from 2 to 10 keV and beam currents of several microamperes were obtained. Si samples were implanted with decaborane ions and the implanted dose measured by current integration was compared with B content obtained by nuclear reaction analysis. Experiments with electrostatic beam deflection show that the large ions survive the transport in the implanter environment and that neutralization is negligible. During implantation, the retained B dose is reduced in comparison with the nominal implanted dose due to sputtering. Dose loss is greater at 200 eV compared to 500 eV. The properties of decaborane ion beams and the prospects of using them for shallow implantation of B into Si are discussed.
Furnace and Rta Injection of Point Defects into CVD-Grown B Doped Si and SiGe
Authors: Bonar Janet M. , Mcgregor Barry M. , Cowern Nick E. B. , Dan Aihua , Cooke Graham A. , Willoughby Arthur F. W. 
Published: April 2011

AbstractThe diffusion of B in Si and SiGe under the influence of point defect injection by Rapid Thermal Anneal (RTA) and conventional furnace anneal is studied in this work. B-doped regions in SiGe and Si were grown by LPCVD, and point defects were injected by RTA or furnace annealing bare, Si3N4 or SiO2 + Si3N4 covered samples in an oxygen atmosphere. Self-interstitial defects will be injected into bare Si while vacancy defects will be injected into Si3N4 covered samples, and inert annealing will occur in SiO2 + Si3N4 covered samples. The annealed and asgrown profiles were determined using SIMS analysis, and the diffusivities extracted by direct comparison of the profiles. Both interstitials and vacancies were injected during furnace annealing of SiGe, as demonstrated by the respective enhancement and retardation of the B diffusion. Enhanced B diffusion in SiGe was observed even for 5 s RTA at 1000°C, with an enhancement factor of ∼2.5. The B in Si diffusivity enhancement for interstitial injection by RTA oxidation was found to be a factor of ∼3 compared to inert anneals, close to the factor for SiGe.
The Source of Transient Enhanced Diffusion in Sub-keV Implanted Boron in Crystalline Silicon
Authors: Napolitani E. , Carnera A. , Privitera V. , Schroer E. , Mannino G. , Priolo F. , Moffatt S. 
Published: April 2011

AbstractThe transient enhanced diffusion (TED) during activation annealing of ultra low energy implanted boron (0.5 keV & 1 keV, 1×1013/cm2 & 1×1014/cm2) in silicon is investigated in detail. Annealing in the temperature range from 450°C to 750°C is either performed directly after implantation or after the removal of a surface layer before annealing. The kinetics revealed two regimes of enhanced diffusion ruled by different decay constants and different activation energies. The dependence of these two processes on implantation energy and annealing temperature is described and explained from the microscopical point of view. The annealings performed after surface layer removal, revealed that the defects responsible for the faster diffusion are located deeper than the defects responsible for the slower process.
An Analytical Model for Field-Enhanced Diffusion of Ionized Impurities in Highly Doped Si
Authors: Sokolovskii Bogdan S. , Monastyrskii Liubomyr S. , Kovtun Roman M. 
Published: April 2011

AbstractAn expression for concentration dependence of diffusion coefficient of ionized impurity in semiconductors which is derived which is valid for the whole range of carrier degeneracy under the condition that the impurity concentration greatly exceeds the intrinsic carrier density. Due to reduction of impurity field screening by mobile carriers at degenerate conditions the diffusion coefficient is shown to be a monotonously increasing function of impurity concentration. It is proved that taking band gap narrowing into account results in a reduction of the diffusion coefficient in comparison with the case of unperturbed band structure. In addition, a decreasing concentration dependence of the diffusion coefficient can be realized at relatively low impurity concentrations.
The Effect of Carbon/Self-Interstitial Clusters on Carbon Diffusion in Silicon Modeled by Kinetic Monte Carlo Simulations
Authors: Pinachoa R. , Jaraíz M. , Gossmann H. J. , Gilmer G. H. , Benton J. L. , Werner P. 
Published: April 2011

AbstractA new model for carbon diffusion in silicon that explains carbon diffusion during annealing at 850°C and 900°C in superlattice carbon structures grown by MBE is implemented using the Monte Carlo atomistic simulator DADOS. Carbon concentrations in the delta layers are 2×1020 cm−3, exceeding by far the solid solubility. The simple kick-out mechanism which incorporates the well established values of the product of diffusivity and equilibrium concentrations of intrinsic point defects and in-diffusion experiments of carbon in silicon does not explain the observed C diffusion profiles. A more detailed analysis of the experiments shows that, in order to fit them, a more unstable Ci is required. Therefore, we include the formation of clusters in the simulations. The formation of carbon/Si self-interstitial clusters promotes the premature break-up of Ci and the increase of the Si self-interstitial concentration in the carbon rich regions and, consequently, provides a better fit to the experiments. The low solubility of carbon in silicon at the annealing temperatures explains why these clusters are formed, even under conditions where the self-interstitial concentration is below the equilibrium value.
Amorphous Mixed TiO2 and SiO2 Films on Si(100) by Chemical Vapor Deposition
Authors: Smith Ryan C. , Taylor Charles J. , Roberts Jeffrey , Hoilien Noel , Campbell Stephen A. , Gladfelter Wayne L. 
Published: April 2011

ABSTRACTAmorphous thin films of composition TixSi1-xO2 have been grown by low pressure chemical vapor deposition on silicon (100) substrates using Si(O-Et)4 and either Ti(O-iPr)4 or anhydrous Ti(NO3)4 as the sources of SiO2 and TiO2, respectively. The substrate temperature was varied between 300 and 535°C, and the precursor flow rates ranged from 5 to 100 sccm. Under these conditions growth rates ranging from 0.6 to 90.0 nm/min were observed. As-deposited films were amorphous to X-rays and SEM micrographs showed smooth, featureless film surfaces. Cross-sectional TEM showed no compositional inhomogeneity. RBS revealed that x (from the formula TixSi1-xO2) was dependent upon the choice of TiO2 precursor. For films grown using TTIP-TEOS x could be varied by systematic variation of the deposition conditions. For the case of TN-TEOS x remained close to 0.5 under all conditions studied. One explanation is the existence of a specific chemical reaction between TN and TEOS prior to film deposition. TEOS was mixed with a CCl4 solution of TN at room temperature to produce an amorphous white powder (Ti/Si = 1.09) and 1HNMR of the CCl4 solution indicated resonances attributable to ethyl nitrate.
Low Temperature Nitridatio of SiO2 Films using a Catalytic-CVD System
Authors: Izumi Akira , Sato Hidekazu , Matsumura Hideki 
Published: April 2011

ABSTRACTThis paper reports a procedure for low-temperature nitridation of silicon dioxide (SiO2) surfaces using species produced by catalytic decomposition of NH3 on heated tungsten in catalytic chemical vapor deposition (Cat-CVD) system. The surface of SiO2/Si(100) was nitrided at temperatures as low as 200°C. X-ray photoelectron spectroscopy measurements revealed that incorporated N atoms are bound to Si atoms and O atoms and located top-surface of SiO2.
Multi-Level Damascene Process Development: Aluminum CMP
Authors: Hansen David A. , Moloney Gerry , Reyes Alex 
Published: April 2011

ABSTRACTThe purpose of this work was to investigate integration of aluminum multi-level damascene devices with the CMP module. Traditionally aluminum is used in the Metal-1 level of device manufacturing and Reverse Ion Etching (RIE) is used to remove the aluminum over layer. However for <0.25-µproportional]m device rules RIE is not a method of choice due to incomplete removal of the over layer leaving stringers that cause shorting, as well as poor With-In Wafer NonUniformity (WIWNU). The result is loss of device yield and process problems for BEOL modules. Integrating aluminum device wafers into the CMP module has its own drawbacks such as immature consumables, i.e., slurry and polishing pads, as well as ease of scratching the soft aluminum interconnect structures. Hence the basis of this work is to highlight the main issues that impede the integration of the aluminum CMP process. Specifically we investigated the origin of deep aluminum scratches and the effect of not completely removing the residue barrier material, which can cause shorting and poor electrical performance. It is argued in this work that the observed deep scratches in the aluminum material are due to the polished debris emanating from the titanium glue layer. Recommendations are made to help to reduce this effect by design modification to the die layout on the patterned wafer and using electrical testing methods to help ascertain the minimum Over Polishing (OP) time required in order to ensure maximum die yield.
Interfacial Fluid Pressure and Its Effects on SiO2 Chemical Mechanical Polishing
Authors: Zhou C. , Shan L. , Hight J. R. , Ng S.H. , Paszkowski A. J. , Tichy J. , Danyluk S. 
Published: April 2011

ABSTRACTIn this paper, the experimental results of interfacial fluid pressure and friction measurements during polishing are presented, as well as their dependence on some major process variables. Under simulated conditions, a sub-ambient fluid pressure was observed, and its magnitude was of the same order of magnitude as the applied polishing load. Since this fluid pressure is non-uniformly distributed, the contact stress, obtained by combining the effects of both applied load and the fluid pressure, is not uniform across the wafer and will result in non-uniform material removal. The mechanism of the presence of the fluid pressure was investigated, and an analytical model was developed to predict the magnitude and distribution of this fluid pressure. The effects of the sub-ambient fluid pressure on material removal rate and profile were tested with thermally grown silicon dioxide on 100mm diameter, P-type (100), single crystal silicon wafers. The polishing experiments show the effect of sub-ambient fluid pressure on polishing rate and profile.
Smoothing Thin Films with Gas-Cluster Ion Beams
Authors: Fenner D.B. , Hautala J. , Allen L.P. , Greer J.A. , Skinner W.J. , Budnick J.I. 
Published: April 2011

ABSTRACTThin-film magnetic sensor and memory devices in future generations may benefit from a processing tool for final-step etching and smoothing of surfaces to nearly an atomic scale. Gas-cluster ion-beam (GCIB) systems make possible improved surface sputtering and processing for many types of materials. We propose application of GCIB processing as a key smoothing step in thin-film magnetic-materials technology, especially spin-valve GMR. Results of argon GCIB etching and smoothing of surfaces of alumina, silicon, permalloy and tantalum films are reported. No accumulating roughness or damage is observed. The distinct scratches and tracks seen in atomic-force microscopy of CMP-processed surfaces, are removed almost entirely by subsequent GCIB processing. The technique primarily reduces high spatial-frequency roughness and renders the topographic surface elevations more nearly gaussian (randomly distributed).
ESR investigations on Ca perovskite
Authors: Chipara M. , Liou Sy-Hwang , Borca C. N. , Shoemaker R. , Adenwalla S. , Dowben P. A. 
Published: April 2011

ABSTRACTElectron spin resonance studies on fine powders of La0.65Ca0.35MnO3, performed in the X band, are reported. The coexistence of paramagnetic and ferromagnetic phases, in a narrow temperature range close to the Curie temperature, is observed. The electron spin resonance measurements do not support the presence of bipolarons above the Curie temperature. Temperature dependence of the ESR linewidth is governed by the hopping of polarons and the corresponding activation energy is about 150 meV above TC.
Structure and Magnetic Properties of Nd-Co-Fe-Si-C Intermetallics
Authors: Sorescu Monica , Grabias A. , Valeanu M. 
Published: April 2011

ABSTRACTIntermetallics of the type Nd2Co15−xFexSi2Cy (x=7; 9; 12 and y=0; 1) were prepared by arc melting in order to study the competing effects of Fe and Co substitutions on the magnetic hyperfine fields as well as the effects of interstitial carbon additions on the symmetry and local magnetic properties in these systems. The investigations were performed by x-ray diffraction, Mössbauer spectroscopy and hysteresis loop measurements. Both site and average hyperfine magnetic field values were analyzed in order to discriminate between the Fe and Co contributions to the local atomic environments in these systems. While a higher Fe content as well as a higher Co content can both lead to an increase in the site magnetic fields, it was found that the model based on hyperfine field distributions provides a better description of the trends observed in hyperfine magnetic fields in these compounds.
Magnetic Behavior and Structure of Electrodeposited, Mechanically Hard Fe-C and Fe-Ni-C Alloys
Authors: Haseeb A. S. M. A. , Hayashi Y. , Masuda M. 
Published: April 2011

ABSTRACTIron-carbon based hard, martensitic alloys are usually produced by conventional high temperature heat treatment. In the present work, the galvanostatic electrodeposition method has been employed to obtain hard Fe-0.96 mass % C and Fe-15.4 mass% Ni-0.70 mass% C alloys at around room temperature. The alloys have been investigated by SEM, XPS, XRD, and microhardness measurements, and their magnetic properties have been studied by vibrating sample magnetometer.The as-deposited alloys were found to possess high mechanical hardness, 750-810 HV. Both alloys exhibit a smoother surface morphology as compared to a non-alloyed iron film obtained under similar electrochemical conditions. The coercive force of the as-deposited Fe-C and Fe-Ni-C alloys is 3930 and 494 A.m−1respectively. In comparison, pure iron film deposited under similar conditions possesses a coercive force of 1592 A.m−1. The Fe-Ni-C alloy has a combination of high mechanical hardness and relatively soft magnetic properties, which may be of interest in potential applications requiring both soft magnetic properties and improved tribological performance. The effects of annealing on the behavior of the alloys are discussed.
Changes in Stress and Microstructure in PtMn/CoFe Bilayers during Annealing
Authors: Bozeman S.P. , Daniels B.J. , Larson D.J. 
Published: April 2011

ABSTRACTPtMn is one of several candidate antiferromagnetic materials for biasing of spin valve giant magnetoresistive (GMR) sensors used in magnetic recording heads. The as-deposited crystal structure of PtMn is face-centered cubic, which is not antiferromagnetic, and it is commonly annealed to transform it to the ordered face-centered tetragonal structure, which is antiferromagnetic. The changes in the thin film stress during this transformation can be up to 1.5 GPa in magnitude. In this work, the stresses in sputter-deposited, PtMn/CoFe bilayers were measured during annealing using a laser-based wafer curvature technique. During annealing, the stress initially increases before approaching a constant level. This behavior was examined for samples with a range of PtMn compositions and varying degrees of PtMn {111} texture. Both the magnitude and rate of change of the stress are sensitive to the composition of the films, but are relatively insensitive to the film texture. These results are discussed in terms of the binary alloy phase diagram.
In Situ Stress and Strain Measurements During the Growth of Cu/Ni (001) Multilayers
Authors: Bigault T. , Bocquet F. , Labat S. , Thomas O. , Marty A. , Gilles B. 
Published: April 2011

ABSTRACTCu/Ni (001) multilayers have been grown by molecular beam epitaxy at room temperature. In-situ electron diffraction and curvature measurements performed during the growth are presented. The average lattice parameter in the equiatomic multilayers evolves gradually towards the alloy lattice parameter. The in-plane lattice parameter of both Cu and Ni evolves continuously towards the bulk lattice parameter with no evidence of pseudomorphic growth. The combination of diffraction and curvature measurements suggests that the Ni on Cu interface is diffuse. This is attributed to the surfactant behaviour of Cu. This results shed new insights into the interesting magnetic properties of Ni films on Cu (001).
Si1−xGex Island Formation by Post-Growth Anneal on Supercritical Layers Grown by RPCVD
Authors: Grimm K. , Vescan L. , Nanver L.K. , Visser C.C.G. , Lüthl H. 
Published: April 2011

ABSTRACTSiGe island layers have been created by post growth anneal on supercritical layers grown at low temperatures (500°C) and high hydrogen pressures (40 Torr). The epitaxial growth has been performed in a commercially available single wafer RPCVD reactor using SiH2Cl2 and GeH4 as precursor gasses. SiGe layers grown under these conditions exceed the critical thickness for the onset of elastic relaxation reported for lower hydrogen pressures as well as the critical thickness for plastic relaxation by more than one order of magnitude. A subsequent anneal step is used to form the islands. This procedure allows some degree of control in the formation of SiGe islands. High island densities and uniform size distributions were achieved. Photoluminescence as well as electroluminescence measurements of these layers show strong emission from SiGe.
Quantum Dot Growth in the Si-Ge-C System Through Multi-Step Procedure
Authors: Wakayama Yutaka , Gerth Gerhard , Werner Peter , Sokolov Leonid V. 
Published: April 2011

ABSTRACTTo fabricate nanometer-sized Ge dots on Si(100), we have investigated multi-step procedure, involving low temperature deposition of a Ge layer, a sub-monolayer C on a Ge wetting layer, a Ge top layer for three-dimensional (3D) dot formation and post-annealing. Effects of each procedure were discussed on the basis of an atomic force microscope study. 10nm-sized Ge dots with a high number density in the order of 1011 cm−2 were grown on the Si(100) substrate by combining each procedure and optimizing experimental conditions, such as deposition temperature, the C layer thickness and post-annealing temperature.
A Quantitative Model of Surface Segregation in III-V Ternary Compounds
Authors: Karpov Sergey Yu. , Makarov Yuri N. 
Published: April 2011

ABSTRACTA quantitative model of surface segregation free from adjustable parameters is suggested for the growth of ternary III-V compounds. In contrast to previous approaches, the model considers the dynamics of surface population by the three elements producing the ternary alloy. The underlying assumption is that the atoms in the adsorption layer are in equilibrium with the crystal bulk. Elastic strain arising in the epitaxial layer due to the lattice constant mismatch with the substrate is found to be one of the key factors affecting segregation. Along with growth temperature, it controls the segregation efficiency and the composition profile evolution in a growing heterostructure. The effect of the V/III ratio, growth rate and other parameters is accounted for. Here, we apply the model to analyze the InGaAs growth by molecular beam epitaxy owing to the vast experimental data available for the model verification. The theoretical predictions show a good agreement with the experimental observations
Strong Photon-Exciton Coupling in the Near-Field Luminescence of Semiconductor Quantum Dots
Authors: Mintairov A. M. , Vlasov A. S. , Merz J. L. , Kovalenkov O. V. , Reynolds J. P. , Vinokurov D. A. 
Published: April 2011

ABSTRACTWe present low-temperature near-field scanning optical microscopy (NSOM) measurements of self-organized InP quantum dots (QD) embedded in a GaInP layer. We observed an anomalously strong increase in the emission energy (∼270 meV) of a single QD by changing the tip-to-surface distance over ∼100 nm in the near-field region. The effect indicates the formation of a near-field nanocavity having extremely high photon-exciton mixing and can be interpreted as the observation of the coupled photon-exciton pair
Effect of Lattice Mismatch on the Decay of Rheed Oscillations During Growth of Strained InGaAs/GaAs Heterostructures
Authors: Nemcsics Àkos , RiEsz Ferenc 
Published: April 2011

ABSTRACTThe decay of the oscillation of the intensity of the specular beam of the reflection high-energy electron diffraction pattern is analyzed during the molecular beam epitaxial growth of strained InGaAs/GaAs heteroepitaxial structures. The oscillations' amplitude was found to decrease exponentially versustime during the InGaAs growth. Further, the decay time constant decreases with InAs mole fraction, indicating that the lattice strain increases islanding during growth. A simple semi-quantitative model based on the growth front roughening is formulated to explain the results. Assuming that the oscillation decay is related partly to the strain and partly due to kinetic effects during growth, a decay component that is solely due to strain can be separated; we find that the onset of increased roughening due to misfit strain component roughly corresponds to the equilibrium critical layer thickness