bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polymer Brush-Lined Membranes for Flow and Filtration Control
Authors: Sevick Edith M. , Bruce Frank A. , Williams David R.M. 
Published: April 2011

ABSTRACTWe describe the flow and filtration control imparted to membranes through the adsorption of polymer brushes onto the interior pores. The brushes exhibit a negative Poisson's ratio, i.e. they swell under shear, and as a result behave as sensors and valves controlling the flow and filtration through the pore. The valve-behavior of brushes adsorbed onto cylindrical pores displays the same constant discharge control but also exhibits a critical shear rate for brush swelling.
Scanning Conduction Microscopy: A Method of Probing Abrasion of Insulating Thin Films on Conducting Substrates
Authors: Dickinson J. T. , Hipps K. W. 
Published: April 2011

ABSTRACTThe use of Scanning Force Microscopy (SFM) to probe wear processes at interfaces is of considerable interest. We present here a simple modification of the SFM which allows us to make highly spatially resolved measurements of conductivity changes produced by abrasion of thin insulating films on metal substrates. The technique is demonstrated on fluorocarbon polymer thin films deposited on stainless steel substrates.
Electroplating of Fluoropolymers using ECR Plasma Deposited TiN as Interlayer
Authors: Weber A. , Dietz A. , Pöckelmann R. , Klages C.-P. 
Published: April 2011

ABSTRACTA novel low temperature process for titanium nitride (TiN) deposition by means of an electron cyclotron resonance (ECR) plasma CVD process was applied to poly(tetrafluoroethylene) (PTFE). The organometallic compound tetrakis(dimethylamido)titanium (TDMAT) introduced into the downstream region of a nitrogen ECR plasma was used as a precursor for TiN deposition at 100°C.The thin TiN films (thickness 15-30 nm) act as interlayers to activate the electroless deposition of copper followed by an electroplating process. Prior to the deposition of the interlayer, the samples were treated on a biased susceptor with argon ions to enhance the adhesion of the TiN interlayer. This metallization procedure avoids the use of toxic and pollutive etching agents and yields adherent copper layers on PTFE.The maximum adhesion of the metal film on PTFE was established to be 13 N/mm2. As shown by atomic force microscopy (AFM), TiN grains were formed on the fluoropolymer surface. Film composition was investigated by secondary ionization mass spectrometry (SIMS).
Adhesion Between Polyimide Films and A12O3 Substrate
Authors: Nakamura Y. , Suzuki Y. , Watanabe Y. , Hirayama S. 
Published: April 2011

ABSTRACTThe adhesive strength of polyimide thin films on an alumina substrate has been studied by the pull test. Polyimide thin films were cured at various temperatures from 300 to 400°C, followed by etching in an oxygen plasma for 3 min. After metallization with chromium and copper, the pull test was carried out. It is found that the adhesive strength increases with an increase of the cure temperature. However the strength deteriorates noticeably at the cure temperature of 400°C. A possible reason for this is the variation of chemical states in the polyimide thin films.
SurfaceSIMS, Secondary Ion Mass Spectrometry Using Oxygen Flooding: A Powerful Tool for Monitoring Surface Metal Contamination on Silicon Wafers
Authors: Smith Stephen P. , Wang Larry , Erickson Jon W. , Chia Victor K. F. 
Published: April 2011

ABSTRACTSecondary ion mass spectroscopy (SIMS) coupled with oxygen flooding of the silicon surface during analysis provides an analytical technique capable of detecting ≤1010 atoms/cm2 of many surface elemental contaminants. Of particular importance to meet the future needs of the semiconductor industry is the current ability to detect Al and Fe contamination at a level of 2×109 atoms/cm2.
A study of Cleaning Performance and Mechanisms in Dilute SC-1 Processing
Authors: Resnick P. J. , Adkins C. L. J. , Clews P. J. , Thomas E. V. , Korbe N. C. 
Published: April 2011

ABSTRACTA statistical design of experiments (DOE) approach has been employed to evaluate the effects of megasonic input power, solution chemistry, bath temperature, and immersion time on particle removal in SC-1 chemistries. Megasonic input power was the dominant factor in the response surface model. Substantially diluted chemistries, performed with high megasonic input power and moderate-to-elevated temperatures. were shown to be very effective for small particle removal. Follow-on studies to the original DOE have led to an investigation of ultradilute SC-1 chemistries with megasonic power. These chemistries ranged from 0 to 1000 ppm of NH4OH and H2O2. Post processing light point defect (LPD) counts differ substantially between bare n and p-type Si<100>, and ambient lighting conditions are shown to influence LPD counts on p-type Si<100>. Solution properties such as pH and oxidation potential have been studied, and an investigation of post processing silicon surface properties is underway.
Time-Dependent Dielectric Breakdown in Thin Intrinsic SiO2 Films
Authors: Suehle J. S. , Chaparala P. 
Published: April 2011

ABSTRACTTime-Dependent Dielectric Breakdown studies were performed on 6.5-, 9-, 15-, 20-, and 22.5- nm thick SiO2 films over a wide range of stress temperatures and electric fields. Very high temperatures (400 °C) were used to accelerate breakdown so that stress tests could be performed at low electric fields close to those used for device operating conditions. The results indicate that the dependence of TDDB on electric field and temperature is different from that reported in earlier studies. Specifically, the electric-field-acceleration parameter is independent of temperature and the thermal activation energy was determined to be between 0.7 and 0.9 eV for stress fields below 7.0 MV/cm.Failure distributions of high-quality current-generation oxide films are shown to be of single mode and have dispersions that are not sensitive to stress electric field or temperature, unlike distributions observed for oxides examined in earlier studies. These results have implications on the choice of the correct physical model to describe TDDB in thin films. The data also demonstrate for the first time the reliability of silicon dioxide films at very high temperatures.
Valence Band Alignment of Ultra-Thin SiO2/Si Interfaces As Determined By High Resolution X-Ray Photoelectron Spectroscopy
Authors: Alay J. L. , Fukuda M. , Bjorkman C. H. , Nakagawa K. , Sasaki S. , Yokoyama S. , Hirose M. 
Published: April 2011

ABSTRACTUltra-thin SiO2/Si(111) interfaces have been studied by high resolution x-ray photoelectron spectroscopy. The deconvolution of the Si 2p core-level peak reveals the presence of the suboxide states Si3+ and Si1+ and the nearly complete absence of Si2+. The energy shifts found in the Si 2p and O is core-level peaks arising from charging effects arc carefully corrected. The valence band density of states for ultra-thin (1.8 - 3.7 nm thick) SiO2 is obtained by subtracting the bulk Si contribution from the measured spcctrum and by taking into account the charging effect of SiO2 and bulk Si. Thus obtained valence band alignment of ultra-thin SiO2/Si(111) interfaces is found to be 4.36 ± 0.10 eV regardless of oxide thickness.
Effects of UV/O3 and SC1 Steps for the HF Last Silicon Wafer Cleaning
Authors: Jeon Hyeongtag , Choi Hyungbok , Cho Y. S. , Ryoo K. K. , Jung S. D. 
Published: April 2011

ABSTRACTAs the size of integrated circuit is scaled down, the importance of Si wafer cleaning has been emphasized. Especially, in the ULSI level device, the cleaning has a great influence on device yields and reliabilities. In this study, we investigate the effects of UV/03 and SCI steps in the HF last cleaning procedures. The UV/O3 and SCI cleaning steps are known to remove the organic contaminants. However, the combination of UV/O3 cleaning step with HF wet chemical solution to remove the metallic impurities has not been studied extensively. We have applied the UV/O3 and SCI steps in the middle of the HF last cleaning procedures and have analyzed Si substrates with TXRF, AFM, I-V, etc. The cleaning splits we applied consist with 4 different types, split 1 (piranha + HF), split 2 (piranha + UV/O3 + HF), split 3 (piranha + SC1 + HF) and split 4 (piranha + UV/O3 + HF repeated 3 times). The contents of metallic impurities were measured with using TXRF and splits 2 and 4 showed low average values of metallic contents. The surface morphologies after each cleaning examined with AFM and the split 3 exhibited rough surface. The electric properties were measured after forming a MOS capacitor with oxide thickness of 250Å. The high leakage current and low breakdown voltage were observed at split 3.
Surface Modification of ZnxCd1-x Te Due to Low Energy Ion Sputtering
Authors: Vijayalakshmi S. , Chen K.-T. , George M. A. , Burger A. , Collins W. E. 
Published: April 2011

ABSTRACTZnxCd1-xTe is a widely used substrate for the epitaxial growth of HgCdTe, which is used in infrared detectors. Results of the effect of sputtering of ZnxCd1-xTe single crystals with low energy Ar beam are reported in this paper. X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) techniques were used to measure the concentration of Zn in these crystals. Selective sputtering of Zn atoms has been observed from freshly cleaved crystals using XPS studies. Sputtering is a common method of cleaning ZnxCd1-xTe crystals in their device preparation and our studies show that this method of cleaning alters the surface which may introduce lattice mismatch on the surface. Surface morphology before and after cleaving the crystals is studied using Atomic Force Microscopy (AFM).
Conducting AFM: Applications to Semiconductor Surfaces
Authors: Murrell Martin P. , O'Shea Sean J. , Barnes Jack , Welland Mark E. , Sofield Carl J. 
Published: April 2011

ABSTRACTThe use of Conducting Probe Atomic Force Microscopy to give nm scale electronic characterisation of surfaces is reviewed. Local conductance, Kelvin Probe work function measurements, Fowler-Nordheim tunnelling and local C-V characterisation techniques are outlined. The principle results of these and their applications to the semiconductor surface and thin film characterisation are discussed. We present tunnelling data from silicon through varying oxide thickness using conducting AFM and scanning Kelvin Probe measurements from sub micron MOS capacitors. The F-N tunnelling technique has also been used on epitaxial silicon surfaces with atomically flat topography.The inherent problems associated with quantitative, reproducible measurements are outlined, and the potential applications of the measurements to surface and thin film technology are discussed.
Growth of MonX by Reactive Laser ablation
Authors: Treece Randolph E. , Horwitz James S. , Donovan Edward , Chrisey Douglas B. 
Published: April 2011

AbstractControl of composition and phase of a series of MoNx thin films has been accomplished by reactive pulsed laser deposition (PLD). Molybdenum foil targets were ablated in a background gas of N2/H2 (10%) at pressures ranging from 40 to 120 mTorr. the MoNx films were deposited simultaneously onto (100) MgO and fused silica substrates. the films were characterized by X-ray diffraction (XRD), temperature-dependent resistivity, and Rutherford backscattering spectroscopy (RBS). the composition, phase, and electronic transport properties were found to depend on N2/H2 pressure, substrate temperature, and substrate orientation. the highest superconducting transition temperature (Tc ) was observed in a hexagonal Mo2N film where Tc (onset) ≈ 8 K. IN general, Tc was observed to correlate most closely with the N/Mo ratio. as the ratio of N/Mo increased above optimal M02N composition, Tc decreased. Films grown on MgO generally had higher N/Mo ratios and hence lower Tc values than films deposited on silic A.
Hyperthermal H Atom Reactions on D/Si(100)
Authors: Buntin Steven A. 
Published: April 2011

AbstractA photolytic source of H atoms is used to probe abstraction and adsorption reactions on the D/Si(100) monodeuteride surface. Surface H and D coverages are determined for H atom exposures, with incident average kinetic energies of 1.0 and 2.8 eV. the D atom depletion probability per incident H atom is 0.3±0.2 for both kinetic energies, and is likely due to abstraction. these results, together with previous studies, indicate that the rates of depletion of surface D and the uptake of H are nominally independent of H atom kinetic energy over the range of about 0.3 to nearly 3 eV.
In-Situ Transmission Electron Microscopy for Analysis of Ion-Beam-Growth Processes
Authors: Pankov Vladimir V. , Levchuk Nikolai E. , Dostanko Anatoly P. 
Published: April 2011

AbstractTwo types of systems for in situ transmission electron microscopy analysis of ion-beam etching, ion-beam sputtering and ion-beam assisted deposition are reported. their design, operational features and some applications are presented. Radiation-stimulated diffusion in Mo-Si heterostructure, early growth of ion-beam sputtered in-Sn, in-Sn-O, ZnS:Mn films and recrystallization of ln-Sn-O films during vacuum post-annealing are studied.
Evaluation of No-Clean Fluxes for High Reliability Applications
Authors: Pope E. , Watson J. , Kennish D. 
Published: April 2011

ABSTRACTA series of rosin mildly activated, halide free, low residue fluxes have been evaluated for use with hot bar reflow of Tape Carrier Packages (TCP) to printed circuit boards (PCB). Materials were studied with respect to their wettability, SIR performance, water reflux extractable ionics and residue levels. Ionic levels were measured by FTIR and Ion chromatography. A flux was selected which has demonstrated acceptable performance in 156C/85%RH 10V biased stress testing.
Thin Film Integral Capacitor Fabricated on a Polymer Dielectric for High Density Interconnect (HDI) Applications
Authors: Paik Kyung W. , Lu Toh-Ming 
Published: April 2011

ABSTRACTThe expanding needs of mixed signal applications of thin film MCM technologies which combine analog, digital, power and opto-electric devices require a wide range of integral, thin film, passive components within the MCM structure. There is a need to incorporate these passive elements into the interconnect structure to reduce component count, decrease substrate area and to improve electrical performance. In this study, we investigated advanced material and processing technologies for the in situ formation of capacitor components during the fabrication of multilayer polymer/copper interconnect structures.Amorphous BaTiO3 film having a dielectric constant of 10 to 40 depending on stoichiometry was deposited on a surface roughness controlled metallized polyimide surface at room temperature using the reactive partial ionized beam (RPIB) technique. Simple metal/insulator/metal(MIM) capacitors were fabricated and characterized. Hundreds of pF capacitance with <10−6 Amp leakage current were obtained depending on the top metal electrode size, dielectric thickness, and stoichiometry of dielectric film. Annealing treatment on dielectric film significantly enhanced the leakage current property. After thermal cycling treatment, it was proved that thin film integral capacitor was reliable enough to be used as a practical MCM application. Process defects control was necessary to improve capacitor yield.
Technique for Measuring Electronic-Based Electro-Optic Coefficients of Ferroelectric Liquid Crystals
Authors: Arnett Kenneth E. , Walba David M. , Drewes Joel A. 
Published: April 2011

AbstractAmong soft organic nonlinear optical materials is a class of recently developed: χ(2)_ enhanced ferroelectric liquid crystals (FLCs). The FLC phase nonlinear susceptibility is enhanced by synthesizing onto the molecules constituting the FLC phase a moiety with an increased hyperpolarizability. The hyperpolarizability of the FLC molecules couples into the permanent, thermodynamically stable, polar order of the FLC phase resulting in a material with an enhanced nonlinear susceptibility. Like other soft organics, the linear and nonlinear optical materials characteristics can be altered by chemical synthesis and mixing.We report on our technique to evaluate the nonlinear optical properties of χ(2)-enhanced FLCs by measuring their high-frequency electro-optic r-coefficients. The technique is broad-band, readily allowing electro-optic coefficient measurement between 100 KHz and 200 MHz. Although the experimental geometry is not conducive for practical device application, it offers a compromise between ease of fabrication and magnitude of nonlinear response. This technique can also be used to evaluate other organic materials such as poled polymers.
Micro-Raman Study of Sol-Gel Grown Pmn-PT Thin Films
Authors: Ching-Prado E. , Tao R. W. , Guo A. R. , Katiyar R. S. , Bhalla A. S. 
Published: April 2011

AbstractThin films of 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (PMN-PT) were prepared by sol-gel technique and deposited on platinum coated-silicon wafer. The thicknesses of the two films were ∼400 nm and ∼550 nm, respectively. Micro-Raman spectra of the PMN-PT films show strong broad bands centered at 50, 136, 276, 450, 510, 556, and 790 cm−1, which are characteristic of PMN formation. Temperature dependent Raman scattering from 290K to 70K did not show any significant change in the bandwidth of the peaks, meaning thereby that the relaxation times of these phonons are practically temperature independent. The bands are interpreted as due to a break down in the phonon momentum conservation within the Brillouin zone, which is associated with some degree of disorder in the material. As a result, the Raman spectrum is a weighted average of the density of phonon states. Micro-Raman measurements in many different places on the films clearly indicate that they are homogeneous. In addition, the differences found in the Raman spectra of the films, particularly the band at 790 cm−1 is discussed. FT-1R measurements of the PMN-PT films present two broad bands around 260 and 550 cm−1, which are characteristic of perovskite structure and are primarily due to motions of oxygen ions. Also, these bands are compared with those found in PMN single crystal, and with those found in other similar systems, such as PLZT and PSN. SEM and XRD techniques have been used for the structural characterization.
Development of Chromophores Based on the Dicyanomethylene Acceptor Group
Authors: Ermer Susan , Lovejoy Steven M. , Leung Doris S. 
Published: April 2011

AbstractWe have used DCM/polyimide guest-host films for a series of device demonstrations, including demonstrations of high speed, low voltage digital and analog switching. Although useful for such demonstrations, DCM tends to out diffuse at polyimide cure temperatures, motivating the search for related compounds with similar activity, transparency, processibility, and greater thermal stability. We have designed, synthesized, and characterized a series of chromophores with related molecular structures. Like DCM, all of these chromophores share the dicyanomethylene [>C=C(CN)2] acceptor group. Some of these compounds are conventional donor-acceptor chromophores, while others fall into the class of lambda-shaped donor-acceptor-donor (DAD) compounds. An acceptor-donor-acceptor (ADA) chromophore has also been prepared and characterized. The donor-acceptor analog studies utilize a variation on the Knoevenagel condensation reaction used to make DCM, substituting isophorone for 4-pyranone to avoid the formation of mixtures. These reactions lead to the DCI series of compounds. We will describe progress in our investigations of these series of compounds.
Epitaxial Growth of GaN Films Produced by ECR-Assisted MBE
Authors: Moustakas T.D. 
Published: April 2011

ABSTRACTThe epitaxial growth of wurtzite and zincblende GaN on (0001) sapphire and (001) Si by the Electron Cyclotron Resonance-assited Molecular Beam Epitaxy (ECR-MBE) method is discussed. We show that films can be grown in the layer-by-layer mode when growth occurs in Ga-rich regime. Surface roughening mechanisms are addressed. The similarity of photoluminescence data of Mg-doped wurtzite GaN films with those of undoped zincblende GaN films suggests that Mg doping facilitates the formation of stacking faults in the wurtzite structure which are nucleation sites for zincblende domains.
Low-Temperature Growth of High Quality InxGa1−xN by Atomic Layer Epitaxy
Authors: Boutros K.S. , Roberts J.C. , McIntosh F.G. , Piner E.L. , El-Masry N.A. , Bedair S.M. 
Published: April 2011

ABSTRACTWe report on the low temperature epitaxial growth of InxGa1−xN with 0≤x≤0.27 by Atomic Layer Epitaxy (ALE). GaN and InGaN single crystal films have been grown by ALE in the temperature range between 600 and 700 °C using the rotating substrate approach. Films were deposited on sapphire substrates using TMG, EdMIn, and NH3 as precursors. Up to 27% indium content has been achieved in the InGaN films. The FWHM of the (0002) InGaN peak by double crystal X-ray diffraction of these films was as small as 5 minutes. Room-temperature photoluminescence (PL) from these films was dominated by band edge emission between 365 nm and 446 nm. AlGaN/InGaN double heterostructures were grown in a hybrid reactor, in which the AlGaN barrier layers were grown by MOCVD and the InGaN active layer by ALE. The structures showed good crystal quality, and sharp PL emission with peak intensity at 410 nm.
GaN Three Dimensional Nanostructures
Authors: Dmitriev V. , Irvine K. , Zubrilov A. , Tsvetkov D. , Nikolaev V. , Jakobson M. , Nelson D. , Sitnikova A. 
Published: April 2011

ABSTRACTWe report on the growth and characterization of three dimensional nanoscale structures of GaN. GaN dots were grown by metal organic chemical vapor deposition (MOCVD) on 6H-SiC substrates. The actual size of the dots measured by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) ranged from ∼20 nm to more than 2 μm. The average dot density ranged from 107 to 109 cm−2. The single crystal structure of the dots was verified by reflectance high energy electron diffraction (HEED) and TEM. Cathodoluminescence (CL) and photoluminescence (PL) of the dots were studied at various temperatures and excitation levels. The PL and CL edge peak for the GaN dots exhibited a blue shift as compared with edge peak position for continuous GaN layers grown on SiC.
Electronic Structure of a Nitrogen Vacancy in Cubic Gallium Nitride
Authors: Gubanov V.A. , Wright A.F. , Nelson J.S. , Fong C.Y. , Klein B. M. 
Published: April 2011

ABSTRACTA nitrogen vacancy in zinc-blende structure gallium nitride (c-GaN) is investigated by the plane-wave pseudopotential (PWPP) and tight binding-linear combination of muffin tin orbitals (TB-LMTO) methods using 32- and 64- atom supercells. The relaxation of the nearest Ga atom to the vacancy site is found to be inward by 0.069 a.u., with a relaxation energy of 0.04 eV/N-atom vacancy. The shell-projected, total and partial densities of states and the charge density maps are obtained to provide detailed information on energy and spatial localization of the N vacancy states.
Electroreflectance from Gallium Nitride Using Second-Harmonic Generation
Authors: Miragliotta Joseph , Wickenden Dennis K. 
Published: April 2011

ABSTRACTThe optical second-harmonic (SH) response of a reverse biased gallium nitride (GaN) film was investigated for SH photon energies near the fundamental absorption edge. With the application of a DC electric field (∼ 100 to 220 kV/cm) along the optical axis of the sample, a strong two-photon resonance was observed in the specular reflected SH signal. This resonance was attributed to electric-field induced SH generation, EFISH, a third-order nonlinear response which arises from an induced polarization that is linearly dependent on the amplitude of the DC field. The EFISH contribution was spectrally localized at the bandedge, demonstrating the potential of SH spectroscopy for analysis of critical points in the band structure of semiconductors.