bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low Temperature CVD Route to Binary and Ternary Diffusion Barrier Nitrides for Cu Metallization
Authors: Kaloyeros Alain E. , Kelsey Jean , Goldberg Cindy , Anjum Dalaver , Chen Xiaomeng , Mirza Jawid , Kumar Kaushik , Arkles Barry , Han Bin , Sullivan John J. 
Published: April 2011

ABSTRACTThe identification of viable diffusion barrier/adhesion promoter material and associated deposition processes is a critical factor in the successful development of structurally and electrically reliable copper based metallization schemes. As feature sizes continue shrinking, such materials are expected to delivery enhanced performance at increasingly thinner layers to allow maximum space utilization by the actual conductor. In this respect, Ta and W based binary and ternary nitrides present promising solutions in view of their hardness, chemical inertness, and thermal stability to high temperatures. Additionally, their availability in amorphous form provides the added benefit of inherent absence of grain boundaries, which usually serve as a primary diffusion path. This paper presents finds from the development of low0temperature (,350°C) CVD processes for the growth of ultrathin Ta, W, Ta-Si, and WSinitride layers for sub−0.18 micron device structures. These processes employ novel inorganic and metal-organic source precursors which allow for the in-situ, one-step, growth of binary and ternary nitrides from appropriate mixtures of the corresponding source precursors. Results will also be discussed from diffusion barrier studies which established performance metris for the applicability of such materials in copper interconnect technologies.
Modelling of Failure Time Distributions for Interconnects Due to Stress Voiding and Electromigration
Authors: Wolfer W. G. , Bartelt M. C. , Dike J. J. , Hoyt J. J. , Gleixner R. J. , Nix W. D. 
Published: April 2011

AbstractA status report is given on a comprehensive modeling project aimed at predicting failure time distributions of interconnect lines. We discuss our novel approach to calculate the evolution of stresses in lines using elastic response functions. It is argued that this approach makes it possible to model the stress and damage evolution in a large ensemble of lines efficiently so that statistically meaningful failure time distributions can be generated.The elastic response functions enable us also to derive a generalized Korhonen equation which includes the effects of mass transport at remote locations. Basic features of this equation are demonstrated with a one-dimensional implementation and its results are compared with the classical Korhonen [8, 9, 10] model.
The Effects of Microstructures on Normal and Early Failures of Interconnects Caused by Electromigration
Authors: Liu Yongkun , Diefendorf R. J. 
Published: April 2011

AbstractMicrostructure plays a key role in reliability of interconnects. However, a quantitative correlation between microstructure and reliability of interconnects is lacking. This paper develops a statistical description of effective diffusivity of interconnects by considering grain boundaries, bulk lattice and line interface diffusion, and introduces a microstructure-based electromigration lifetime prediction model for normal failures of interconnects. Further, the probability of early failure of interconnects due to a severe microstructural inhomogeneity is calculated. Using the sub-population failure model, the mean time to failure of interconnects, with a range of microstructures from polycrystalline to hyper-bamboo, are simulated. The reported increase in lifetimes of wide polycrystalline lines with increasing w/d is mainly ascribed to reservoir effects of bonding pads in test structures. Reported lifetime prediction model may be used as guidance for circuit design and accelerated testing.
Determination of the Effects of Strain on Electrical Resistivity in Patterned Interconnects
Authors: Sanchez John E. , Reilly Christopher J. 
Published: April 2011

AbstractSensitive measurements of electromigration-induced resistance changes in metallization interconnects have been previously interpreted as due to precipitation effects, vacancy concentration changes and local stress changes (due to the piezoresistance effect). The latter have the potential for characterizing the early stages of electromigration-induced diffusive phenomena prior to larger scale effects such as voiding and subsequent localized joule heating which seriously complicate the interpretation of small resistance changes. However the utility of such “early" measurements is also hindered by lack of an accurate knowledge of the stress coefficient of resistivity as a proper characterization of the change in strain state of the Al. We present measurements of the effects of volumetric strain on the resistivity of Al interconnects where the strain is induced by thermal expansion mismatch between the Al and surrounding passivations. The piezoresistance effect is characterized by properly accounting for the degree of interconnect constraint (and volumetric strain) induced by thermal expansion mismatch as a function of temperature for both passivated and unpassivated lines. Sensitive interconnect resistance versus temperature measurements for differently constrained interconnects (with different volumetric strains) thus allows for the measurement of the piezoresistance effect. Other effects such as solute or vacancy concentration changes with temperature are minimized since the measurements are performed by cooling the passivated and unpassivated lines from room temperature to approximately 70K, rather than by significant heating above room temperature. We determine the piezoresistance coefficient, defined as dρ/dɛv, where ρ = resistivity and ɛv = volumetric strain, to be approximately 1.5−5 Ω-cm, in rough agreement with previous work. The interpretation of sensitive resistance measurements as volumetric strains in isolated sections of interconnects undergoing electromigration-induced diffusion processes is described for specialized test structures.
Critical Length and Resistance Saturation Effects in Al(Cu) Interconnects
Authors: Gall M. , Müller J. , Jawarani D. , Capasso C. , Hernandez R. , Kawasaki H. 
Published: April 2011

AbstractA new test structure for electromigration failure analysis of via-interconnect metallization schemes was developed. Multi-via/interconnect chain arrays were used in a parallel/serial testing arrangement. Due to improved statistical sampling, the multi-via test structures enabled measurement of drift velocity phenomena at via/interconnect interfaces with a very limited number of test devices per stressing condition, and without reducing the signal to noise ratio. Furthermore, realistic, production-type metallization schemes can be characterized without usually required “traditional” drift velocity-type metal stacks incorporating highly resistive shunt-layers. Critical length effects were investigated as a function of line length and current density. At interconnect lengths close to the critical Blech-length, resistance saturation effects were encountered and used for calculations of the critical current density-length product, (jl)*. Furthermore, a new resistance saturation model was developed and found to correlate well with the acquired data. Critical length effects can accurately be measured and used for length-dependent interconnect performance evaluation on the device-level.
Local Channel Temperature Measurements on Pseudomorphic High Electron Mobility Transistors by Photoluminescence Spectroscopy
Authors: Landesman J.P. , Martin E. , Depret B. , Fily A. , Braun P. 
Published: April 2011

AbstractThe technique of spatially resolved photoluminescence (PL) spectroscopy was used to determine the local channel temperatures on GaAs/GaInAs/GaAlAs pseudomorphic high electron mobility transistors. By focusing a laser beam onto the different regions of the DC-biased transistor, it is shown that the channel temperature can be determined from the energy shift of one of the peaks in the PL spectra, with a spatial resolution of about 1 µm and a temperature resolution in the order of 1 °C. In particular, an asymmetry in the temperature distribution between the drain and source sides is observed. Using this approach, detailed temperature maps of the devices were obtained, as a function of the gate-source voltage VGS. These experimental temperature values are also compared with predictions derived from an analytical model of the thermal resistance in these devices.
Mems as Temperature Sensors During High Temperature Processing
Authors: Tada H. , Abramson A. R. , Nieva P. , Zavracky P. , Miaoulis I. N. , Wong P. Y. 
Published: April 2011

AbstractIn high temperature processing of microelectronics such as rapid thermal processing (RTP), an accurate measurement of temperature is critical in fabricating defect-free devices. Currently, temperatures during such processes are measured using thermocouples or pyrometers. However, accurate measurements with thermocouples are troublesome due to the difficulties in holding the thermocouples in place and maintaining good thermal contact. A further drawback for thermocouples is that they are highly intrusive. For pyrometers, optical interference effects and partial transparency limit their applicability and the local temperature of wafers near the electronic devices are difficult to measure using pyrometer due to relatively large spot size. Microelectromechanical systems (MEMS) technology is being used in developing innovative temperature sensor (T-MEMS), which allow an ex-situ examination of the maximum temperature reached during a thermal process by creating a permanent change in structure at high temperatures. The performance of the device relies on the thermophysical properties of the materials; specifically, the Young's modulus, thermal expansion coefficient, and the ultimate strength must be considered for silicon, and silicon nitride. Through careful experimental design and accurate modeling of their structural behavior, the high-temperature material properties can be determined using the T-MEMS and calibrated furnaces.
Finite-Element Modeling of Residual Stress in SiC Diaphragms
Authors: DeAnna Russell G. , Zorman Christian A. , Mehregany Mehran 
Published: April 2011

AbstractFinite-element modeling of the residual stress due to expansion-coefficient mismatch between a 3C-SiC film and Si substrate is presented. The change in residual stress after bulk etching of the silicon substrate to create a suspended diaphragm is also presented. 1, 2, or 3 μm-thick 3C-SiC films are grown at 1600 K on a 100 mm diameter, 500 μm-thick, (100) Si substrate using atmospheric pressure chemical vapor deposition (APCVD) in a cold-wall, vertical-geometry, RF-induction-heated reactor. An axisymmetric, finite-element analysis (FEA) of the cooling and etching process is presented using the ANSYS54 finite-element package. The etching process is modeled by removing the Si elements in the etched region after cooling from film-growth to room temperature. The results show that residual stress in the diaphragm decreases from 3 to 8 percent after etching.
Resonance Method: An Attractive Way to Evaluate Mechanical Properties of Thin Gold Films
Authors: Attia P. , Hesto P. 
Published: April 2011

AbstractMicromechanical test structures have been developed for evaluating mechanical properties of thin gold films. Using micromachining techniques, gold cantilever beams of different geometry (typically 40 to 100-µm-long, 2-µm-thick and around 1-µm-wide), were fabricated. These cantilevers were resonated by electrical excitation in a scanning electron microscope (SEM) and Young's modulus, Q-factor and fatigue properties were deduced from these experiments. The longest cantilevers showed a slight upward curvature which allowed the internal stress gradient to be evaluating.
Round-Robin Tests of Modulus and Strength of Polysilicou
Authors: Sharpe W. N. , Brown S. , Johnson G. C. , Knauss W. 
Published: April 2011

AbstractThe Young's modulus and strength of polysilicon specimens manufactured in the same production run were measured in four different laboratories. Specimens subjected to in-plane bending were tested at U. C. Berkeley and at Failure Analysis Associates, and tensile measurements were made at Caltech and Johns Hopkins. All specimens were produced at the Microelectronics Center of North Carolina (MCNC).In bending, the Young's modulus for specimens nominally 2 µm thick was measured as 174 GPa and 137 GPa; whereas in tension, a value of 132 GPa was obtained. Modulus values of 136 GPa and 142 GPa were measured in tension on specimens nominally 1.5 µm and 3.5 µm thick. Strengths of the brittle polysilicon were 2.8 and 2.7 GPa in bending and 1.3 GPa for both thicknesses in tension.These preliminary results were presented atSymposium N - Microelectromechanical Structures for Materials Researchat the Materials Research Society meeting in April 1998. This paper is a short overview of the test methods — each of which is described elsewhere — and a documentation of the results presented at that time.
Strength of Surface Micromachined Diaphragms
Authors: Yang Xing , Siu Frances M. , Tai Yu-Chong 
Published: April 2011

AbstractThis paper presents the study of the strength of surface micromachined diaphragms. It is found that the diaphragm strength strongly depends on the diaphragm boundary conditions. A new fabrication technique which does not change the mask and fabrication process is proposed to improve the common step-up boundary condition. Test diaphragms with diameters from 200 µm to 800 µm and three different boundary conditions have been fabricated using silicon nitride/PSG and silicon nitride/polysilicon surface micromachining processes. Experimentally, it is found that the strength of the diaphragms is significantly improved with the new boundary conditions. The application of this technique to other surface micromachined structures is also described.
Synthesis and Intermolecularly Mediated Assembly of Organic Pigment in Hybrid Coating Films
Authors: Yan Y. , Duan Z. , Chen D.-G. , Chaudhuri S. Ray 
Published: April 2011

AbstractThe insoluble, strongly hydrogen bonded organic pigment of 3,6-bis-(4-chlorphenyl)-l,4- diketopyrrolo [3,4-c] pyrrole was transiently blocked by adding carbamate groups, and consequently incorporated into organic-inorganic hybrid matrices by a sol-gel process. The homo- (pigment-pigment) and hetero-intermolecular (pigment-matrix) interactions were found to control both the assembly and dispersion of pigment molecules in the hybrid coating films. A weaker interaction between matrices and pigment molecules results in aggregation of the carbamate pigment in the methyl-silicate films. A stronger interaction forms a homogenous dispersion and coloration of the phenyl-silicate films. The as-prepared methyl- and phenylsilicate films doped with the organic pigment were distinguished by a morphology change and a blue (hypsochromic) shift in absorption from 550 to 460 nm. Thermal treatment can remove the carbamate groups and in-situ form the organic pigment in the hybrid films.
Nanocomposites From Polymers and Layered Minerals
Authors: Fischer H. R. , Gielgens L. H. , Koster T. P. M. 
Published: April 2011

AbstractComposite materials consisting of polymeric matrix materials and natural or synthetic layered minerals like clays were prepared by using special compatibilizing agents between the two intrinsically non-miscible materials. These compatibiliseres are block- or graft copolymers combining one part of the polymer identically and/or completely miscible with the organic polymer (matrix compound) an another part compatible/miscible with the natural mineral. The interaction between the first part of the compatibiliser is preferentially an ionic interaction or an interaction via H-bonds. This interaction leads to a separation of the mineral into single sheets and a subsequent homogeneous incorporation of these sheets into the polymer matrix material.
Inorganic- Organic Hybrid Materials For Photonics
Authors: Lal M. , Joshi M. , Kumar D. N. , Friend C. S. , Winiarz J. , Asefa T. , Kim K. , Prasad Paras N. 
Published: April 2011

AbstractMolecular materials comprised of inorganic:organic composites are of considerable interest in photonics, optoelectronics and biophotonics. We report broad band lasing and tunable filters in sol-gel processed poly (p-phenylene vinylene) PPV: Silica composites. Optical power limiting in near IR wavelength region is also reported in dye doped PPV: silica multiphasic nanocomposites. For making hybrid inorganic: organic composites the reverse micelle mediated synthesis technique has been exploited to synthesize dye encapsulated metal oxide particles, thiocresol capped CdS clusters, Cul and AgI nanoparticles. These particles were dispersed in polymeric matrix for applications in photoconductivity and photorefractive measurements.
Optical and Electronic Properties of Conjugated Polymer -Nanocluster Semiconductor Hybrid Systems
Authors: Narayan K. S. , Manoj A. G. , Nanda J. , Kuruvilla B. A. , Sarma D. D. , Claflin B. , Lucovsky G. , Claflin B. , Lucovsky G. 
Published: April 2011

AbstractConjugated polymers are intensively pursued as candidate materials for emission and detection devices with the optical range of interest determined by the chemical structure. On the other hand the optical range for emission and detection can also be tuned by size selection in semiconductor nanoclusters. The mechanisms for charge generation and separation upon optical excitation, and light emission are different for these systems. Hybrid systems based on these different class of materials reveal interesting electronic and optical properties and add further insight into the individual characteristics of the different components. Multilayer structures and blends of these materials on different substrates were prepared for absorption, photocurrent (Iph), photoluminescence (PL) and electroluminscence (EL) studies. Polymers chosen were derivatives of polythiophene (PT) and polyparaphenylenevinylene (PPV) along with nanoclusters of cadmium sulphide of average size 4.4 nm (CdS-44). The photocurrent spectral response in these systems followed the absorption response around the band edges for each of the components and revealed additional features, which depended on bias voltage, thickness of the layers and interfacial effects. The current-voltage curves showed multi-component features with emission varying for different regimes of voltage. The emission spectral response revealed additive features and is discussed in terms of excitonic mechanisms.
Controlling the Particle Size of Quantum Dots Incorporated in Hybrid Materials
Authors: Monte Francisco Del , Xu Yuhuan , Mackenzie John D. , Claflin B. , Lucovsky G. 
Published: April 2011

AbstractSemiconductor PbS quantum dot-doped Ormocers were successfully prepared by the sol-gel technique. Ormocers preparation was based on the use of trifunctional silane precursors at the solution stage. Formation of PbS particles took place in the pores of the Ormocers through lead precursor reaction with H2S gas. It was observed that temperature was an important factor in the reaction leading to the first appearance of PbS particles. The dot size of PbS was controlled through chemical interaction with the non-hydrolyzed groups of the trifunctional silane precursors. These groups prevent uncontrolled nucleation and aggregation processes during the particle formation and growth. The control of particle size was studied at different conditions for nucleation and aggregation. Determination of the average particle size was done by XR-Diffraction. Optical absorption spectra were also measured at the UV-VIS wavelength range. Absorption edge blue shifts show the quantum confinement effect in these materials.
Physical Performance of Polymer Systems Containing Micro and Nano Fillers
Authors: Gao Z. Justin , Tsou Andy H. , Claflin B. , Lucovsky G. 
Published: April 2011

AbstractThis paper deals with polymer systems containing micro and nano organic/inorganic fillers. A general framework is established to study the effects of the filler and matrix properties on the physical performance of filled polymer systems. A model is proposed to predict elastic moduli, break strength and break strain of polymers containing fillers. The model, based on rigorous continuum mechanics principles, takes into consideration the filler/filler interactions, incorporates the nonlinear synergistic effects of fillers, and agrees very well with experimental measurements.
Synthesis and Characterization of Hybrid Materials Obtained Through Hydrolysis of Alkoxysilanes and Vanadium Alkoxides
Authors: Alonso B. , Maquet J. , Viana B. , Sanchez C. 
Published: April 2011

AbstractNew hybrid materials made of polydimethylsiloxane species (chains and cyclic species) crosslinked at the molecular level by O=V(O-)3 units with a very high degree of homogeneity and dispersion even for a V/Si ratio of 10% have been synthesized and characterized mainly by 29Si, 51V MAS NMR, DSC and DMA. The structure of these hybrids is very different from those proposed for the other dimethylsiloxane-transition metal oxide systems. These dimethylsiloxanevanadates copolymers exhibit higher glass transition temperatures than usual PDMS and a very sharp variation of the loss factor tanδ. These hybrid materials exhibit at low temperature a strong phosphorescence usually associated to a Ligand to Metal Charge Transfrer process.
Introduction of Organic Moieties into Transition-Metal Oxide Matrices via Phosphonate Groups
Authors: Mutin P.H. , Delenne C. , Medoukali D. , Corriu R. , Vioux A. 
Published: April 2011

AbstractTransition metal oxide / phenylphosphonate hybrids with M/P ratios ranging from 1 to 5, (M= Ti, Zr) and metal phosphonates (M/P = 0.5) have been prepared by a sol-gel process involving in a first step the non-hydrolytic condensation between metal alkoxide and phosphonic acid leading to M-O-P bonds, followed by the hydrolysis-condensation of the remaining M-OR groups. The composition, texture and structure of the materials were investigated using EDX, TGA, XRD, IR and 31P NMR.
Thermoplastics Modified with Nanoscale Inorganic Macromers
Authors: Haddad Timothy S. , Mather Patrick T. , Jeont Hong G. , Romo-Uribe Angel , Farrist Amy R. , Lichtenhant Joseph D. 
Published: April 2011

AbstractWe have taken a unique approach to the synthesis and study of hybrid organic/inorganic materials. Our method involves synthesizing nano-size inorganic P1R7Si8O12 clusters which contain seven inert “R” groups for solubility and only one functional “P” group for polymerization. This strategy permits the synthesis of melt processable, linear hybrid polymers containing pendent inorganic clusters and allows us to study the effect these clusters have on chain motions and polymer properties. The synthesis of norbomenyl-based polyhedral oligomeric silsesquioxane (POSS) macromers, their ring opening metathesis copolymerizations with varying amounts of norbornene, and analysis of the effect of the pendent POSS group is presented. The mechanical relaxation behavior and microstructure of norbornyl-POSS hybrid copolymers have been examined for their dependencies on the mole fraction of POSS-norbornyl monomer, as well as for potential sensitivity to the seven inert “R” groups present in each POSS macromer. POSS copolymerization is observed to enhance the α-relaxation temperature, Tα, in proportion to the mole fraction of POSS-norbornyl comonomer. Interestingly, however, the magnitude of this dependence is larger for POSS-norbornyl comonomer possessing cyclohexyl groups (CyPOSS) than for cyclopentyl groups (CpPOSS). While POSS copolymerization yields only slight enhancement of the tensile storage modulus measured near room temperature, at temperatures lower than a strong mechanical relaxation (β-relaxation near T = -75 °C), there is a significant POSS-reinforcement of the storage modulus.