bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diamagnetic Susceptibility of Micron Thick a-Si:H Films Measured via Proton NMR: A Probe of Structural Disorder
Authors: Baugh J. , Han D. X. , Kleinhammes A. , Wang Q. , Wu Y. 
Published: April 2011

ABSTRACTMagnetic susceptibility is predicted to be sensitive to structural disorder in the group IV elemental semiconductors. A proton nuclear magnetic resonance (NMR) technique is shown to precisely measure bulk magnetic susceptibilities (χ) of hot-wire (HW) CVD a-Si:H films as- deposited on quartz substrates. Differences in χ correlate with growth rate, but not with hydrogen content or deposition temperature. Qualitative agreement is found between smaller diamagnetic susceptibility (less average disorder) and desirable electronic properties measured by photo- and dark conductivity on the same samples. Comparing films with similar hydrogen distribution and content (as evidenced by the NMR spectra) allows the unambiguous identification of the importance of overall Si network structural disorder in the metastability of a-Si:H.
Silicon-Carbon Alloys Synthesized by Electron Cyclotron Resonance Chemical Vapor Deposition
Authors: Moran Mark B. , Johnson Linda F. 
Published: April 2011

ABSTRACTSilicon-carbon alloys were deposited by electron cyclotron resonance chemical vapor deposition (ECR-CVD) using either halogenated or non-halogenated precursors for the Si and C sources. Halogenated precursors were chosen for initial experiments to try to reduce the H content and to improve the microstructure of the silicon carbide (SiCx) films. While a wide range of compositions has been deposited using the halogenated precursors, only a limited range has been deposited so far with the non-halogenated precursors. Electron spectroscopy for chemical analysis (ESCA) and Fourier transform infrared (FTIR) spectroscopy show that compositions ranging from near-stoichiometric SiCx to extremely C-rich can be deposited by controlling the deposition temperature, plasma power and C/Si ratio of the halogenated precursors. At the highest C/Si-precursor ratio, the deposited film is electrically conductive with a measured resistivity of 0.067ω-cm, contains only 3-atomic-percent Si and should be considered a Si-doped carbon (C:Si) film. The excellent transparency, especially that of the C:Si films, allowed the assignment of FTIR absorption bands that are usually masked by graphitic inclusions and other impurities. A weak absorption band at 1180cm−1 was found to correlate with the electrical conductivity of the films and was attributed to the asymmetric “bond-and-a-half” Si=C stretch in a Si=C=C functional group where the pi electrons are distributed equally between the three atoms. Additional results show etching of the substrate by reactive Cl from the halogenated precursors can have a dramatic effect on the microstructure, porosity and moisture stability of the films. For experiments involving halogenated precursors, the C:Si films are much more stable than the near-stoichiometric SiCx because C:Si is deposited at lower plasma powers that do not etch the Si substrate. Finally, preliminary results show that near-stoichiometric SiCx films deposited using non-halogenated precursors are much more stable with respect to moisture incorporation than those deposited with halogenated precursors.
Capacitance Voltage Characteristics of Polysilicon–Polysilicon Oxide–Polysilicon Structures for Three-Dimensional Memory
Authors: Lindsey John R. , Kalkur T. S. 
Published: April 2011

ABSTRACTThree-dimensional integration offers a dramatic reduction in chip area required per bit and has long been a research objective. Three-dimensional integration with thin film transistors (TFTs) requires detailed parametric analysis with techniques such as Capacitance-Voltage (CV) Characterization. CV analysis of polysilicon TFTs uses polysilicon-oxide-polysilicon thin film structures. Most of the CV analysis involving polysilicon available to date, however, is with polysilicon-oxide-bulk silicon structures. In this paper, we report the results of modeling andmeasurement of the CV characteristics of polysilicon-polysilicon oxide-polysilicon for doped and undoped polysilicon. To increase the conductivity of the polysilicon, elevated temperatures were used for measurement. CV measurements matching the theoretical curves were made for these polysilicon thin films. Oxide thickness, series and shunt resistance were extracted and correlated to process problems and splits.
A Junction Field Effect Transistor Based on Hydrogenated Amorphous Silicon
Authors: Caputo D. , Cesare G. de , Nascetti A. , Kellezi V. , Palma F. 
Published: April 2011

ABSTRACTAn hydrogenated amorphous silicon junction field effect transistor suitable for analog and digital applications is presented. The device is constituted by a p+ - i - n− junction, with the drain and source contacts patterned on the n-doped layer and the gate electrode patterned on the p+ doped layer. As in the crystalline case, the device is a voltage-controlled resistor, and its drain-source resistance can be varied, with a voltage applied to the gate electrode, by modulating the width of the depletion layer extending into the n-type channel.The doping value of this layer has been chosen as a trade-off between high value of channel conductivity and a relatively low defect density in the material. The manufactured device, with W/L=5000/200 μm, shows the typical current-voltage curves of a JFET. In particular, at low VDS, the current presents the linear behavior of the triode zone, where the JFET operates as a linear resistance whose value is controlled by the gate voltage. At higher VDS the JFET works in the pinch-off region as a dependent current generator.First results are very encouraging, since we have achieved transconductance values of 10−6 V/A, which are comparable to those of state of the art TFT.
Response Time Measurements and Flying Spot Technique in Microcrystalline Silicon Solar Cells
Authors: Schwarz R. , Sanguino P. , Koynov S. , Fernandes M. , Maçarico F. , Louro P. , Vieira M. 
Published: April 2011

ABSTRACTTransverse charge collection in a p-i-n structure based on microcrystalline silicon and lateral transport in a single intrinsic layer were analyzed using transient photoconductivity (TPC), steady-state photocarrier grating analysis (SSPG), and the flying spot technique (FST). Photocurrents were excited either with HeNe laser light (633 nm, intensity about 20 mW/cm2) or with 5 ns pulses from a Nd:YAG laser (532 nm, peak power of about 500 kW/cm2 with 5 mJ pulses). The response time τR varied greatly from about 3 ms at low intensity down to a few μs under pulsed laser excitation. The minority carrier diffusion length LD measured by FST in diode structures was usually larger than values obtained from the SSPG method applied to intrinsic microcrystalline layers.
Resistivity and Hall Voltage Investigation of Phosphorus Segregation in Polycrystalline Si1-xGex Thin Films
Authors: Qin W. , Ast D. G. , Kamins T. I. 
Published: April 2011

ABSTRACTDopant segregation in atmospheric-pressure, chemically vapor deposited (APCVD), ~300 nm thick, polycrystalline Si0.95Ge0.5 and Si0.9Ge0.1 thin films, implanted at 80 KeV with 6×1013 to 5×1014 P/cm2 and annealed at 800 °C for 1 hr, was investigated using a combination of Hall and conductivity vs. temperature measurements. Hall measurements, feasible only in heavier doped films, showed that 29% of the phosphorus in Si0.9Ge0.1 and 42% of phosphorus in Si0.95Ge0.05 was electrically inactive. The loss was attributed to dopant segregating to grain boundaries. The density of grain boundaries states was also found to increase slightly with increasing Ge content, from 3.6×1012/cm2 in Si0.95Ge0.05 to 4.4×1012/cm2 in Si0.9Ge0.1.
Polycrystalline Silicon Thin Films For Microelectronic Applications
Authors: Guliants Elena A. , Song Young J. , Anderson Wayne A. 
Published: April 2011

ABSTRACTPolycrystalline silicon thin films with a thickness of 0.5-2μm were grown on 25nm thick Ni prelayers by d.c. magnetron sputtering from a Si target. In contrast to the conventional sputtering, the use of a thin Ni film allows the production of high crystallinity silicon at a temperature of 475°C and higher. The Ni disilicide grains formed at the Ni - growing Si film interface provide sufficient sites for the epitaxial growth of Si. The Si films with resistivity of 102-103Ω-cm possess a carrier lifetime of up to 11μs and a diffusion length of up to 3.4 μm, which makes them applicable to various microelectronic devices. As an example, Schottky diodes fabricated on 0.5μm thick Si films exhibit a forward-to-reverse current ratio of 107. The technique is easily implemented on a variety of substrates.
Nanoscale Elastic Imaging of Aluminum/Low-k Dielectric Interconnect Structures
Authors: Shekhawat G. S. , Kolosov O.V. , Briggs G.A.D. , Shaffer E. O. , Martin S. , Geer R. E. 
Published: April 2011

AbstractA new characterization tool based on ultrasonic force microscopy (UFM) has been developed to image the nanometer scale mechanical properties of aluminum/low-k polymer damascence integrated circuit (IC) test structures. Aluminum and polymer regions are differentiated on the basis of elastic modulus with a spatial resolution ≤ 10 nm. This technique reveals a reactive-ion etch (RIE)-induced hardening of the low-k polymer that is manifested in the final IC test structure by a region of increased hardness at the aluminum/polymer interface. The ability to characterize nanometer scale mechanical properties of materials used for IC back-end-of-line (BEOL) manufacture offers new opportunities for metrological reliability evaluation of low-k integration processes.
Circuit-Level and Layout-Specific Interconnect Reliability Assessments
Authors: Hau-Riege S.P. , Thompson C.V. , Hau-Riege C.S. , Andleigh V.K. , Chery Y. , Troxel D. 
Published: April 2011

AbstractWe have developed a methodology and a prototype tool for making computationally efficient circuit-level assessments of interconnect reliability. A key component of this process has been the development of simple analytic models that relate the reliability of the complex structures in layouts to the simpler straight, junction-free lines of uniform width that are typically used in lifetime tests. We have considered interconnect trees as the fundamental reliability units, where trees can have multiple junctions and limbs, and can also have width variations. We have developed analytic methods for identifying trees which are immune to failure, and have demonstrated that computationally simple techniques lead to the identification of a large fraction of the trees in a circuit as immune to failure (i.e., that they are ‘immortal’). These trees therefore need not be considered in further analyses. Using simulations and analytic treatments we have also developed default models which allow estimation of the reliability of the remaining trees. These models have been tested and validated them through experiments on simple tree structures with junctions and line-width transitions. Our prototype circuit-level reliability analysis tool projects the reliability of circuits based on specific layouts, and provides a rank listing of the reliability of mortal trees. This allows the user to accept the assessment as is, to carry out more accurate but computationally-intensive analyses of the least reliable trees, or to modify the layout or process to address reliability concerns and reanalyze the reliability.
Stressmigration Behavior of Multilevel Ulsi Alcu-Metallizations
Authors: Fischer A.H. , Zitzelsberger A.E. , Hommel M. , von Glasow A. 
Published: April 2011

AbstractWith decreasing geometries of metal interconnects the demands on metallization reliability increase rapidly. In addition to electromigration, stress-induced voiding becomes a major problem, influencing lifetime and functionality of integrated circuits. This paper summarizes our studies on stressmigration behavior of various AlCu-multilevel metallizations. A model for an estimation of the median time to failure is presented.
Structure and Property Characterization of Porous Low-k Dielectric Constant Thin Films using X-ray Reflectivity and Small Angle Neutron Scattering
Authors: Lin Eric K. , Wu Wen-li , Jin Changming , Wetzel Jeffrey T. 
Published: April 2011

AbstractHigh-resolution X-ray reflectivity and small angle neutron scattering measurements are used as complementary techniques to characterize the structure and properties of porous thin films for use as low-k interlevel dielectric (ILD) materials. With the addition of elemental composition information, the average pore size, porosity, pore connectivity, matrix density, average film density, film thickness, coefficient of thermal expansion, and moisture uptake of porous thin films are determined. Examples from different classes of materials and two analysis methods for small angle neutron scattering data are presented and discussed.
Fabrication of Air-Gaps Between Cu Interconnects for Low Intralevel k.
Authors: Bhusari Dhananjay M. , Wedlake Michael D. , Kohl Paul A. , Case Carlye , Klemens Fred P. , Miner John , Lee Byung-Chan , Gutmann Ronald J. , Lee J.J. , Shick Robert , Rhodes L. 
Published: April 2011

AbstractWe present here a method for fabrication of air-gaps between Cu-interconnects to achieve low intralevel dielectric constant, using a sacrificial polymer as a ‘place holder’. IC compatible metallization and CMP processes were used in a single damascene process. The air-gap occupies the entire intralevel volume between the copper lines with fully densified SiO2 as the planer interlevel dielectric. The width of the air-gaps was 286 nm and the width of the copper lines was 650 nm. The effective intralevel dielectric constant was calculated to be 2.19. The thickness of the interlevel SiO2 and copper lines were 1100 nm and 700 nm, respectively. Further reduction in the value of intralevel dielectric constant is possible by optimization of the geometry of the metal/air-gap structure, and by use of a low k interlevel dielectric material.In this method of forming air-gaps, the layer of sacrificial polymer was spin-coated onto the substrate and formed into the desired pattern using an oxide or metal mask and reactive-ion-etching. The intralevel Cu trench is then inlaid using a damascene process. After the CMP of copper, interlevel SiO2 is deposited by plasma-CVD. Finally, the polymer place-holder is thermally decomposed with the decomposition products permeating through the interlevel dielectric material. The major advantages of this method over other reported methods of formation of air-gaps are excellent control over the geometry of the air-gaps; no protrusion of air-gaps into the interlevel dielectric; no deposition of SiO2 over the side-walls, and no degradation of the interlevel dielectric during the formation of air-gap.
Characterization and Integration in Cu Damascene Structures of AURORA, an Inorganic Low-k Dielectric
Authors: Donaton R. A. , Coenegrachts B. , Sleeckx E. , Schaekers M. , Sophie G. , Matsuki N. , Baklanov M. R. , Struyf H. , Lepage M. , Vanhaelemeersch S. , Beyer G. , Stucchi M. , Roest D. De , Maex K. 
Published: April 2011

AbstractAURORA films, which have a Si-O-Si network with –CH3 terminations, were characterized and integrated into Cu single damascene structures. The relatively low carbon concentration (∼ 20%) and the very small pore size (∼ 0.6 nm) found could be advantageous during integration of AURORA. Integration of AURORA into Cu single damascene structures was successfully achieved. Suitable resist strip processes, which are critical for Si-O-C type materials, were developed, resulting in trenches with satisfactory profiles. After a complete single damascene process, a interline dielectric constant value of 2.7 was found for line spacing down to 0.25 µm.
A Three-phase Model for the Structure of Porous Thin Films Determined by X-ray Reflectivity and Small-Angle Neutron Scattering
Authors: Wu Wen-li , Lin Eric K. , Jin Changming , Wetzel Jeffrey T. 
Published: April 2011

AbstractA methodology to characterize nanoporous thin films based on a novel combination of high-resolution specular x-ray reflectivity and small-angle neutron scattering has been advanced to accommodate heterogeneities within the material surrounding nanoscale voids. More specifically, the average pore size, pore connectivity, film thickness, wall or matrix density, coefficient of thermal expansion, and moisture uptake of nanoporous thin films with non-homogeneous solid matrices can be measured. The measurements can be performed directly on films up to 1.5 µm thick while supported on silicon substrates. This method has been successfully applied to a wide range of industrially developed materials for use as low-k interlayer dielectrics.
Electromigration-Induced Stress Interaction between Via and Polygranular Cluster
Authors: Park Young-Joon , Choi In-Suk , Joo Young-Chang 
Published: April 2011

AbstractWe have investigated the stress interaction between via and polygranular cluster in the pure Al line using 1-dimensional computer simulation. The conventional belief was that the fastest stress evolution at the via occurs when the polygranular cluster is just below (or above) the via. However, the electromigration induced stress at the via would be faster when a cluster is apartfrom via because the stress interaction between via and clusters may assist electromigration. We simulated the time that the via reaches a certain stress value as a function of the distance of the cluster. It gives a specific distance where the time was minimum (i.e the fastest stress evolution). We named the position as the Fastest Stress Enhancing Polygranular cluster Position (FaSEPP). As a function of the current density, the FaSEPP decreases.
Real Time, In Situ Curvature Measurements of Epitaxial YBCO Films on MgO
Authors: Boyd D. , Tripathi A. , Gallivan M. , Musolf J. , Rosakis A. , Atwater H. , Goodwin D. 
Published: April 2011

AbstractWe have implemented coherent gradient sensing (CGS) to measure in situ, curvature and changes in curvature induced by temperature and O2 flow on thin film YBCO on MgO (001) substrates. CGS is a novel, real-time, full-field optical technique that provides a direct map of the components of the curvature tensor across the entire surface of the wafer. We have examined a well-characterized,700 nm thick YBCO film on a square 1”× 0.5mm MgO substrate with increasing temperature from 25 to 760°C and find the curvature increasing with temperature, although not always spatially uniform. By Stoney's equation, we relate the observed curvature to the thermal mismatch of the film and substrate where the maximum observed stress in orthogonal sample orientations is 1.2 and 1.4 GPa. For wafers under varying oxygen partial pressures, we observe dramatic local changes in the CGS interferograms, which we relate to the tetragonal to orthorhombic phase transformation YBCO exhibits as it cools in oxygen.
Simulation of 3D Films Deposited by Glancing Angle Deposition Using 3D-Films
Authors: Smy T. , Vick D. , Brett M. J. , Dew S. K. , Wu A. T. , Sit J.C. , Harris K. D. 
Published: April 2011

AbstractA new fully three dimensional (3D) ballistic deposition simulator 3D-FILMS has been developed for the modeling of thin film deposition and structure. The simulator may be implemented using the memory resources available to workstations. In order to illustrate the capabilities of 3D-FILMS, we apply it to the growth of engineered porous thin films produced by the technique of GLancing Angle Deposition (GLAD).
Laser Ablation Of Solid Ozone
Authors: Nonaka Hidehiko , Nishiguchi Tetsuya , Morikawa Yoshiki , Miyamoto Masaharu , Ichimura Shingo 
Published: April 2011

AbstractSpecies ablated from solid ozone by a UV laser were investigated using a time-of-flight method through a quadrupole mass filter. The results show that UV-laser ablation of solid ozone can produce a pulsed ozone beam with a translational energy far above that of room temperature. Highconcentration ozone from an ozone jet generator is solidified on a sapphire substrate attached to a copper block which is cooled to 30 to 60 K on a cryocooler head and the solid ozone is irradiated by pulsed laser light from a KrF laser (248 nm). The ablated species were a mixture of ozone and molecular oxygen as well as atomic oxygen due to photodissociation of ozone. At a substrate temperature of 30 K, the total amount of ablated ozone increases as the laser fluence increases to 13 mJcm−2. Beyond this fluence, enhanced decomposition of ozone occurs. Gaussian fitting of the time-of-flight signals of the ablated ozone reveals an average thermal energy exceeding 1,500 K. The velocity also increases when the laser fluence enters saturation at 2,300 K at 13 mJcm−2.
Optical and Structural Characteristics Of Gold Nanocrystallites Embedded in a Dielectric Matrix
Authors: Sharma A.K. , Muth J.F. , Kvit A. , Narayan J. , Kolbas R.M. 
Published: April 2011

AbstractWe have fabricated Gold (Au) crystallites in amorphous alumina matrix by pulsed laser deposition. The characterization of these multilayer sequences was performed by high resolution transmission electron microscopy (HRTEM) and optical transmission measurements. TEM studies revealed the morphology and the microstructure of these composites. The optical transmission spectra showed characteristic surface plasma resonance of Au particles confined by the host dielectric matrix. These resonances fall in the visible spectral range. The importance of pulsed laser deposition in fabricating these composite films is discussed.
Tantalum Nitride Thin Films Synthesized by Pulsed Nd:YAG Laser Deposition Method
Authors: Kawasaki Hiroharu , Namba Kazuya Doi. Jun , Suda Yoshiaki 
Published: April 2011

AbstractTantalum nitride (TAN) films have been deposited on silicon substrates by using a pulsed Nd:YAG laser deposition method. Experimental results suggest that the substrate temperature is one of the most important parameters to prepare crystalline tantalum nitride thin films. Glancing-angle X-ray diffraction patterns show that the films deposited at Ts ≤ 300 °C are almost amorphous. and crystalline Ta6N2.57 films are obtained at Ts ≥ 500 °C. Grain size of the film increases with increasing substrate temperature.
Laser Micromachining of Metallic Mold Inserts for Replication Techniques
Authors: Pfleging W. , Meier A. , Hanemann T. , Gruhn H. , Gahr K.-H. Zum 
Published: April 2011

AbstractThe laser microcaving (LMC) of steel is performed with cw Nd:YAG laser radiation. LMC enables a “clean” patterning process with only a small amount of debris and melt. During LMC the formation of a Ni-enriched interface layer and an oxide surface layer may be observed. The formation of these reaction layers as well as the etch rate and the surface quality strongly depend on the chemical composition of the steel and the process parameters. Surface qualities with an roughness of about Ra(center line average)=300 nm can be realised. The ablation rates are in the range of 106 µm3/s. With excimer laser radiation a further improvement of surface topographies can be achieved via laser planarisation. Mold inserts are manufactured by LMC, and microstructures composed of PMMA are successfully demolded by using the Ultraviolet light induced Reaction Injection Molding (UV-RIM) or Photomolding technique. CE(Capillary Electrophoresis)-Chips made of PMMA are successfully demolded, and the functionality of the CE-Chips is demonstrated.
Fluctuations of Step Positions at KDP Crystal Faces
Authors: Rashkovich Leonid N. , Shustin Oleg A. , Chernevich Tamara G. 
Published: April 2011

ABSTRACTApplying atomic force microscopy in single string scanning mode, dependence of fluctuations of step shifts on KDP crystal faces on time was determined during crystallization from solution. It was shown that fluctuation amplitude grows proportionally to t1/4. On prism faces fluctuations at dissolving were bigger than at growth and bigger than on bipyramid faces. Amplitude of fluctuations was not dependent on distance between steps. Interpretation of experimental results and computation of elementary parameters of crystallization was done based on theory of V.V.Voronkov.