bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sintering of Amorphous Si3N4 Nanoclusters: A Molecular Dynamics Study of Stress Analysis
Authors: Wang Jinghan , Tsuruta Kenji , OmeItchenko Andrey , Kalia Rajiv K. , Vashishta Priya 
Published: April 2011

AbstractWe investigate the onset and growth of the neck between amorphous Si3N4 nanoclusters at zero and finite pressures. Local stress fluctuations and atomic self-diffusion in the interface region are found to be responsible for neck formation. External pressure has a dramatic influence on the rate of sintering.
Adhesion In NiAl-Cr From First Principles
Authors: Raynolds James E. , Smith John R. , Srolovitz David J. , Zhao G.-L. 
Published: April 2011

AbstractWe have calculated the work of adhesion (i.e. energy for rigid fracture) and peak interfacial stress for NiAl, Cr, and NiAl–Cr using self-consistent density functional calculations to obtain the complete energy vs. separation curve for each system. Our calculations indicate that the work of adhesion is largest for Cr and smallest for NiAI while those for interfaces of NiAI with Cr are intermediate. We have also estimated that segregation processes could alter the work of adhesion for the AlNi/Cr interface by up to 20% since Al tends to segregate to the free NiAl surface while Ni tends to segregate to the AlNi/Cr interface.
Preparation Of Metal Nitrides Via Laser Induced Photolytic Decomposition Of Metal-Amides
Authors: Narula Chaitanya K. , Maricq M. Matti 
Published: April 2011

ABSTRACTIrradiation of {[(CH3)3Si]2N}3Y, Zr[N(C2H5)2]4, and Nb[N(C2H5)2]4 by the 1.064 μm line of a pulsed Nd:YAG laser results in the decomposition of Zr[N(C2H5)2]4 and Nb[N(C2H5)2]4 while {[(CH3)3Si]2N}3Y remains unaffected. The decomposition is photolytic and is accompanied by a visible emission tracing the path of the incident beam. The decomposition products form corresponding carbide/nitrides on pyrolysis in vacuum and nitrides on pyrolysis in an ammonia atmosphere. The spectroscopic investigation of the visible emission, and the pyrolysis of the decomposition products to metal nitrides is described.
Produiion of a-Si1-x Cx:H powders using radiofrequency glow discharges of silane and methane mixtures.
Authors: Costa J. , Viera G. , Zhang R. Q. , Andújar J. L. , Pascual E. , Bertran E. 
Published: April 2011

ABSTRACTa-Si1-x Cx:H powders have been produced in radiofrequency glow discharges of SiH4 and CH4. Samples produced in discharges with different gas flow ratios (R=[CH4] / [SiH4]+[CH4], R ∼ 0.2 to 0.95) were analyzed by several techniques: Infrared spectroscopy, transmission electron microscopy and thermal desorption spectrometry of hydrogen. The microstructural properties of the a-Si1-x Cx:H powders obtained ranged between those previously reported in silicon particles and those of amorphous carbon particles. As a general rule, the particles, whose diameter ranged between 5 and 400 nm in diameter, showed an amorphous microstructure and high hydrogen content. Infrared spectroscopy showed that the hydrogen was mainly located on the particle surface and in microvoids forming CHi and/or SiHi (i=2,3) groups.The hydrogen was removed from the powder by thermal annealing (< 700°C) under vacuum. Anlysis of the a-Si1-x Cx:H powders after this thermal treatment revealed new microstructural and optical features.
Structure and Properties of TiC, VC and TiC/VC Thin Films Deposited by Pulsed Laser Deposition
Authors: Krzanowski J. E. , Leuchtner R. E. 
Published: April 2011

ABSTRACTA study has been conducted on the mechanical, tribological and chemical properties of pulsed laser deposited (PLD) TiC, VC and TiCNC thin films. The TiC films were deposited at 375°C and 5 mTorr Ar, while the TiCNC films were deposited from a composite target at 475°C at pressures of base vacuum and 50 mTorr Ar. XRD analysis revealed the films had the expected B1 structure, although XPS analysis showed a significant oxygen content. Tribological studies were conducted using a ball-on-disk test, and the wear behavior depended on the surface condition and film composition. One TiCNC film exhibited little wear but caused significant ball wear, indicating mixed carbide films are promising candidates for wear-resistant coatings.
CP-Mas NMR AND In-Situ FTIR Study of AIN Surface Reactivity
Authors: Monie S. A. , Aurentz D. J. , Pantano C. G. 
Published: April 2011

ABSTRACTThe hydrolytic stability of aluminum nitride (AlN) is an important issue from the standpoint of technology development of AlN as an electronic packaging material. Although numerous studies have been made of the hydrolysis of AlN and characterization of the reaction products, an understanding of the interaction between surface sites and molecular species is still lacking.A combination of Magic-Angle-Spinning Nuclear Magnetic Resonance (MAS NMR) and in-situ Fourier Transform Infrared (FTIR) spectroscopies was used to study the surface reactivity of AlN. The specimens used were specially fabricated self-supported AIN films of high-surface-area (∼25 m2/g), made by nitridation of sol-gel derived pseudoboehmite (AIO(OH)). The in-situ FTIR spectra suggest the formation of a surface layer on the AlN films upon storage. MAS NMR was used to further characterize the surface layer. Using the chemical shifts obtained by 1H-27Al Cross Polarization (CP) MAS NMR experiments, we were able to identify the surface cation sites. The assignment of these sites to Al3+ cations in either tetrahedral coordination with nitrogen or octahedral coordination with oxygen was used to monitor the evolution of the surface upon exposure to the atmosphere. The results indicate that high-surface-area AlN rapidly acquires a surface layer (probably AlO(OH)/Al(OH)3) upon exposure to the atmosphere.
Production of a Novel, Self-Assembled, Collagenous Matrix Mimicking the Hierarchical Structure of Native Aligned Connective Tissue
Authors: Pins G. D. , Christiansen D. L. , Patel R. , Silver F. H. 
Published: April 2011

AbstractThe primary goal of the biomaterials scientist and tissue engineer is to create a biocompatible implant which mimics the mechanical and morphological properties of the tissue being replaced.In vitroexperimentation has documented the propensity of soluble type I collagen to self-assemble and form microscopic collagen fibrils with periodic banding analogous to native collagen fiber. Our laboratory has further investigatedin vitroself-assembly by incorporating several of the “natural” processes into a multi-step fiber formation procedure which generates macroscopic collagen fiber from its molecular constituents. Results of uniaxial tensile tests and ultrastructural analyses indicate that these coextruded and stretched collagen fibers have mechanical properties and fibrillar substructure comparable to that observed in native collagen fiber.
Polypyrrole - A Potential Candidate for Stimulated Nerve Regeneration
Authors: Shastri V. R. , Schmidt C. E. , Kim T.-H. , Vacanti J. P. , Langer R. 
Published: April 2011

AbstractThe proposed research is aimed at gaining a fundamental understanding of in vitro nerve cellbiomaterials interactions, with the immediate goal of engineering materials to specifically enhance expression of the neuronal phenotype. Long term goals include (1) optimizing the innervation (connection) of the host neurons with implanted bioartificial tissue constructs and, (2) facilitating the regeneration of damaged peripheral and central nerves. In this study, the interactions of neuronal like PC-I12 cells with the electrically conducting polymer, polypyrrole, (PP) have been investigated. It has been shown by quantitative image analysis that neurite extensions of PC-12 cells are more pronounced on PP surfaces as compared to tissue culture polystyrene. Application of an electrical stimulus to cells cultured on PP film significantly increased (based on morphological evaluation) the expression of neurites in these cells compared to controls. Tissue compatibility and transected sciatic nerve regeneration studies in rat models show that PP films invoke little negative response and support nerve regeneration.
Formation of Titanium Dioxide Containing Calcium Phosphate Crystallites: A New Process
Authors: Piveteau Laurent-Dominique , Schlapbach Louis , Gasser Beat 
Published: April 2011

AbstractA method for producing titanium dioxide (TiO2) containing hydroxyapatite (HA) crystallite isproposed. Solutions of CaCI2+H3PO4 and TiCL4+HCI combined with KOH are used to precipitatefirst the HA and then the TiO2.The precipitate is then sintered between 900°C and 1000°C for 18 to48 hours. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Energy DispersiveX-ray Analysis (EDX) and scanning electron microscopy (SEM) have been used to determine thecrystallinity, the chemical composition and structure of the samples.
Silicon (Oxy)Nitride Thin Films Deposited by Lpcvd From SiCl2H2-NH3-N2O Mixtures Of Variable Composition
Authors: Davazoglou D. , Iliadis A. A. 
Published: April 2011

AbstractSilicon (oxy)nitride thin films were deposited on (100) 4″ silicon substrates in a conventional LPCVD reactor at 812°C and 230 mTorr, using mixtures of SiCl2H2 -NH3-N2O of variable composition in order to evaluate their optical properties for potential applications in SOI based Si technology. The depositions were carried out keeping the flow of SiCl2H2 and NH3 constant at 20 and 60 sccm respectively while that of N2O was varying between 0 and 180 sccm. Optical reflection measurements within the range 190 to 860 nm, performed on our films were analyzed within the Forouhi-Bloomer model (Phys. Rev. B34, 7018 (1986)) for amorphous semiconductors. From the analysis of the optical spectra, the constants of the model were derived. It was shown that the refractive index of the films varies between the limits set by those of silicon nitride and silicon dioxide, the increase of the N2O flow implying a decrease of the refractive index of the films. The film thicknesses were also derived from the analysis of the optical spectra. Capacitance - voltage measurements made on Metal-Insulator-Semiconductor (MIS) structures using our films as the insulator, have shown that, the electric charge density within the dielectric initially increases and then decreases with increasing the amount of oxygen into the deposition ambiance. Our films are suitable for optoelectronic applications in SOI structures compatible with C-MOS technology.
Strain Effects in InP Dots in between Barriers of GaInP
Authors: Pistol Mats-Erik , Anand Srinivasan , Carlsson Niclas , Hessman Dan , Landin Lars , Persson Christer , Samuelson Lars , Seifert Werner 
Published: April 2011

AbstractWe have investigated the photoluminescence emission energy of InP dots as a function of cap layer thickness. We find a strong blue-shift with increasing cap layer thickness. The strain tensor in the dot as well as in the surrounding matrix has been modelled using finite element methods and the band-gap has been calculated using deformation potential theory. We find good agreement between calculation and experiment. For uncapped dots we find that the emission energy is lower than for biaxially strained InP, and is indeed close to unstrained InP.
Molecular Beam Epitaxial Growth of ZnSe, ZnSSe and ZnMnSSe Layers on GaAs Substrates for Blue-Green Laser Structures
Authors: Chen Y. P. , Saginur M. , Kim C. C. , Sivananthan S. , Smith D. J. , Tsen S.-C.Y. 
Published: April 2011

AbstractSingle layers of ZnSe, ZnSxSe1−x., and Znl−y.MnySxSe1−x., were grown on the GaAs(001). Realtime reflection high energy electron diffraction was used to study the initial growth of ZnSe(001) on GaAs(001) under different conditions. Exposure of the GaAs substrate to Se flux before growth led to three-dimensional growth, whereas exposure to Zn flux led to two dimensional-growth. ZnSxSe1−x., and Znl−y.MnySxSe1−x., (energy gap less than 2.9 eV) layers with the lattice constant closely matched to that of GaAs have been grown with a good reproducibility.
Incorporation of fluorine into the n-type (AIxGayIn1−x−y)as System
Authors: Hayafuji N. , Yamamoto Y. , Fujii N. , Sonoda T. , Takamiya S. 
Published: April 2011

AbstractIn order to elucidate the degradation of the electrical properties of AlInAs/GaInAs high electron mobility transistors during thermal treatment due to the fluorine contamination, the material dependence of this phenomenon has been investigated in AIxGayIn1−x−y As and AlxGayIn1−x−y P systems. The thermal degradation is found to be peculiar to the material containing both of AlAs and InAs, and most serious degradation occurs when the compositional ratio of AlAs to InAs is 1:1. It is also observed that donor-fluorine bonds are formed in the thermally annealed n-type AlInAs layers. The thermal degradation is thought to be due to the fscattering effect of the donorfluorine complex.
Oxidation Resistant Dilute Copper (Boron) Alloy Films Prepared by DC-Magnetron Cosputtering
Authors: Hymes S. , Kumar K. S. , Murarka S. P. , Wang W. , Lanford W. A. 
Published: April 2011

AbstractTo enhance the corrosion resistance and reliability of the proposed copper interconnections in silicon integrated circuits, alloying with small amounts thermodynamically favorable elements has been pursued. In the present investigation dilute copper (boron) alloy thin films (in boron concentration range of 0-4 at % in copper) were deposited by DC magnetron co-sputtering using a high purity copper and Cu-4 at % B targets. Films were then annealed in Ar-3% H2, pure Ar, vacuum, and air ambients in the temperature range of 200–500°C. Sheet resistance, Rutherford backscattering, x-ray diffraction measurements were made to characterize the films. The residual resistivity of the as-deposited alloy films was found to be 5.3 μΩ-cm/at %. To obtain sufficiently low working resistivity, an alloy content below 0.5 at % is suggested for application as a potential “metallization material. The addition of boron, which is the common dopant in Si, to the copper films offers considerable oxidation protection. The resulting oxidation rates are considerably lower than that for pure copper films. All this will be presented and discussed.
Characteristics of Cu-Pd Films Grown by Simultaneous Chemical Vapor Deposition from Metalorganic Precursors
Authors: Bhaskaran V. , Atanasova P. , Hampden-Smith M. J. , Kodas T. T. 
Published: April 2011

AbstractThe strategy of adding alloying elements during the chemical vapor deposition (CVD) of copper to improve the reliability of copper films was investigated. Deposition of Cu-Pd alloy films was demonstrated using low-pressure CVD with (hexafluoroacetylacetonato)- copper(I)(vinyltrimethylsilane) [(hfac)Cu(I)vtms] and palladium(II)bis(hexafluoroacetyl- acetonate) [Pd(hfac)2] in the temperature range of 100-200 ° C in a cold-wall differential reactor. High growth rates of 100-500 nm/min and high-purity films as confirmed by Auger electron spectroscopy (AES) were obtained. As-deposited alloy films showed low resistivities (˜ 2.3 μΩcm) at palladium concentrations below 3 wt. %. A high degree of conformality was observed on sub-half-micron trenches with aspect ratios greater than 3.5:1. The co-deposition of copper and palladium resulted in significant inhibition of palladium growth as compared to the independent palladium deposition.
Plasma Assisted Chemical Vapor Deposition of Aluminum For Metallization In Ulsi
Authors: Kim Dong-Chan , Kim Young-Soung , Joo Seung-Ki 
Published: April 2011

AbstractAn aluminum thin film for ultra large scale integrated circuits(ULSI) metalization has been formed by PACVD using DMEAA(Dimethylethylamine alane) as a precursor. The selectivity was lost but the conformal step coverage was still maintained when the hydrogen plasma was added to conventional CVD process so that perfectly planarized metalization could be obtained.Comparing to thermal CVD, the reflectivity as well as the resistivity could be much improved especially when the film was deposited on SiO2. The deposition rate and the resistivity of PACVD Al thin films deposited on various substrates such as Si, TiN and SiO2 were compared with those of thermal CVD Al thin films.
The Chemical Vapor Deposition of Al-Cu Films Utilizing Independent Aluminum and Copper Organometallic Sources in a Simultaneous Deposition
Authors: Healy Matthew D. , Norman John A. T. , Hochberg Arthur K. 
Published: April 2011

AbstractThe chemical vapor deposition (CVD) of aluminum is now gaining accceptance as a viable metallization technology for the fabrication of sub-0.5 micron interconnects. The incorporation of 0.5% copper into these aluminum films to enhance their electromogration resistance has been achieved by a number of different approaches. These techniques include the sequential CVD of the individual metals and the consecutive growth of CVD Al / PVD Cu followed by an interdiffusing thermal anneal. The potentially more elegant and streamlined solution explored in this paper is the simultaneous deposition of Al and Cu by CVD. A key requirement of this approach is the selection of copper precursors which are stable, volatile and free from oxygen and fluorine. The absence of the latter two elements is essential due to the high probablity of their extraction from the copper precursor by aluminum to form involatile aluminum oxyfluoride species. In our investigation of simultaneous Al/Cu we have utilized two well known aluminum hydride based precursors (DMAH and DMEAA) with two different copper precursors and we herein report the successful deposition of Al-Cu alloys using this approach. A discussion is presented of the dependence of the resulting Al-Cu film quality upon the choice of Al and Cu precursors used in addition to the CVD process parameters utilized for film growth.
Comparison of Cvd and Pvd Tungsten for Gigabit-Scale Dram Interconnections
Authors: Drynan John M. , Koyama Kuniaki 
Published: April 2011

AbstractThe characteristics of blanket CVD-W and PVD-W films with and without TiN/Ti underlayers have been investigated in terms of both materials properties such as resistance, stress, morphology, crystallinity, and composition, and prospective applications such as for DRAM bit line interconnections. The presence of a TiN underlayer has been found to induce preferential growth of dominant W (110) crystal orientation for both CVD-W and PVD-W whereas absence of TiN results in a W film of mixed W (110), (200), and (211) crystallites. Sheet resistance measurements of both blank films and conductor lines have shown that a 200nm-thick PVD-W film yields a lower resistance than a similar film with TiN underlayer and hence larger total thickness. This correspondence of W (110) intensity with resistance implies that reduction of the (110) oriented crystallites within a W film can yield lower resistances. Thus, by elimination of the TiN/Ti underlayer, monolayer PVD-W or CVD-W with a PVD-W underlayer can be effectively adapted to quarter-micron conductors for bit line interconnections and related structures in DRAM memory and other ULSI devices.
Encapsulation of Silver Via Nitridation of Ag/Ti Bilayer Structures
Authors: Zou Y. L. , Alford T. L. , Adams D. , Laursen T. , Tu K.-N. , Morton R. , Lau S. S. 
Published: April 2011

AbstractAg/Ti bilayer films deposited on silicon dioxide substrates were annealed in ammonia ambient in the temperature range of 400 - 600 °C. Rutherford backscattering spectrometry (RBS) and Auger electron spectroscopy (AES) have shown that Ti segregates to both the surface to form a TiN(O) layer and to the Ti/SiO2 interface to form a Ti-oxide/Ti-silicide bilayer. The annealed bilayer structure had minimal Ti accumulations in Ag. Resistivity values of ˜2 μΩ-cm were obtained in encapsulated Ag bilayer films, which are comparable to that of the as-deposited. X-ray analysis confirmed the absence of intermetallic phase transformation.
Improvement in Wet Etch of TiW Fusible links in AlCu/TiW/PtSi Metallization for 0.8μm BICMOS
Authors: Nagalingam Samuel , Parikh Suketu , Sharpe Steve , Anderson Larry , Ross Ron 
Published: April 2011

AbstractIn our 0.8μm BICMOS process flow, TiW fusible links are defined by concentrated H2O2 wet etching. Our investigation to improve uniformity, reproducibility and reliability of TiW wet etching showed that in our etch system, the flow characteristics were the most critical. There is a tradeoff between TiW residues between metal lines and the amount of undercut of the TiW fuses: longer etch times to remove residues result in more undercut. With improved flow dynamics and optimum etch time, we achieved less residue and lower undercut. Results of the pre-etch treatment which reduces lot-to-lot induction time variation were encouraging. When the AlCu/TiW/PtSi metal stack resided on a P+/N junction, we observed an enhanced etching of the TiW due to a photovoltaic effect.
On Advanced Interconnect Using Low Dielectric Constant Materials as Inter-Level Dielectrics
Authors: Zhao Bin , Wang Shi-Qing , Anderson Steven , Lam Robbie , Fiebig Marcy , Vasudev P. K. , Seidel Thomas E. 
Published: April 2011

AbstractIn high performance integrated circuits, low dielectric constant (low-ε) materials are required as inter-level dielectric (ILD) for on-chip interconnect to provide advantages in high speed, low dynamic power dissipation and low cross-talk noise. A variety of low dielectric constant materials, which include fluorinated silicon-oxide, porous silica and porous organic materials, chemical vapor deposited and spin-on deposited (SOD) organic materials, have been developed or are under development to fulfill this need. In this paper, we first review the need and integration architecture of low-ε materials for on-chip interconnect. Then, we discuss the consequence of using low-ε materials as ILD in advanced interconnect with emphasis on the ILD electrical characteristics and the interconnect reliability. Although the focus is on several new promising SOD low-ε materials, the developed evaluation methodology is applicable to other type low-ε materials as well.
Thermal Stability and Interaction Between SiOF and Cu Film
Authors: Mei Yu-Jane , Chang Ting-Chang , Sheu Jeng-Dong , Yeh Wen-Kuan , Pan Fu-Ming , Chang Chun-Yen 
Published: April 2011

AbstractIn this work, we study the thermal stability and interaction between SiOF and Cu. Blanket SiOF films with various F concentration were deposited by PE-CVD. A dielectric constant as low as 3.2 was obtained. Copper were deposited on these SiOF and a series of post-deposition anneal were performed. Dielectric constant of SiOF was measured after deposition and again after anneal. AES and SIMS depth profile are utilized to determine the interdiffusion between Cu and SiOF under different annealing conditions. Breakdown voltage and dielectric constant were determined form C-V and I-V measurement using a MIS ( Cu/ SiOF/ p-Si) diode. This results of leakage current measurement and flat band shift measurement suggest that the fluorine in the SiOF film will retard the cu diffusion.
Do Alkali Metal Anions (M−) Exist in Zeolite A?
Authors: Barker P. D. , Anderson P. A. , Dupree R. , Kitchin S. , Edwards P. P. , Woodall L. J. 
Published: April 2011

AbstractRecent NMR studies by Nakayama et al. on sodium zeolite A saturated with potassium metal have implied the presence of the anionic Na− species. This, if confirmed, would represent the first observation in a zeolite and opens up a wide range of possibilities for mixed metal zeolitic systems. We report the results of a number of metal combinations, using both sodium and potassium forms of zeolite A as hosts, studied by ESR, solid state MAS-NMR and powder neutron diffraction.
Continuum and Stochastic Modeling on the Role of Gel Microstructure in Zeolite Crystallization
Authors: Tsapatsis Michael , Vlachos Dionisios G. 
Published: April 2011

AbstractContinuum and stochastic mathematical models are introduced describing zeolite nucleation and crystal growth from precursor gels. Model predictions are in agreement with existing experimental results. For example, the maximum in the nucleation rate profile under constant supersaturation is observed well before substantial crystallization occurs. Moreover, simulations indicate a strong influence of the gel microstructure on apparent crystallization kinetics, as well as particle size and morphology.