bluuebunny/crossref_metadata_2025_split huggingface dataset:
Scaling of Hafnium-based High-k Dielectrics
Authors: Triyoso Dina H. , Hegde Rama I. , Gregory Rich , Gilmer David C. , Schaeffer James K. , Samavedam Srikanth B. , Kaushik Vidya , Rochat Nevine 
Published: April 2011

AbstractIn this paper, various approaches to extend scalability of Hafnium-based dielectrics are reported. Among the three crystal phases of HfO2 (monoclinic, cubic and tetragonal), the tetragonal phase has been reported to have the highest dielectric constant. Tetragonal phase stabilization by crystallizing the thin HfO2 using a metal capping layer and by adding zirconium is demonstrated. The microstructure, morphology, optical properties and impurities of HfxZr1-xO2 dielectrics (for 0<x<1) are discussed. Subtle but important modification to high-k / Si interface characteristics resulting from addition of Zr into HfO2 is reported. To further boost the dielectric constant of hafnium-based dielectrics, incorporation of TiO2, which has been reported to have high dielectric constant, is explored. HfxZr1-xO2/TiO2 bilayer films were fabricated. 30 Å TiO2 films were deposited on a 5, 8, 12 or 15 Å HfxZr1-xO2 underlayer to determine the minimum thickness needed to maintain good thermal stability with Si substrate. CV and IV results indicated that 12-15 Å is the optimal thickness range for the HfxZr1-xO2 underlayer. A dielectric constant as high as 150 for TiO2 layer is extracted from TiO2 thickness series deposited on12 Å HfxZr1-xO2 underlayer. In addition to increasing the k-value of Hafnium-based dielectrics, it is important that the threshold voltage of these high-k devices is low. Here we report the use of thin Al2O3 capping layers to modulate PMOS threshold voltages. About 100 mV reduction in threshold voltage is achieved by capping HfO2 with a 5Å Al2O3 film. Finally, dielectric scaling by modifying the Si/high-k interfacial layer is attempted. Nitrogen incorporation into HfxZr1-xO2 is shown to be a simple and effective method to lower the capacitance equivalent thickness (CET) of Hafnium-based dielectrics.
Effect of Systematic Changes of Ti and Hf Si-oxynitride Alloys by Nitrogen Incorporation as a Bond Constraint on Electrical and Material Properties
Authors: Lee Sanghyun , Lucovsky Gerry , Fleming L. B. , Luning Jan 
Published: April 2011

AbstractWe have investigated the effect of Si3N4 content in (Ti(Hf)O2)x(Si3N4)y(SiO2)1-x-y pseudo-ternary alloys by tracking systematic changes of electrical properties, including electrically active defects. Results from Soft x-ray photoelectron spectroscopy (SXPS) studies indicate no detectable hole traps for Ti/Hf Si oxynitrides with Si3N4 content >35%; these alloys have equal concentrations of Ti(Hf)O2 and SiO2, ~30-32%, and additionally are stable for annealing in Ar ambients to temperatures of 1100°C. Derivative near edge x-ray absorption spectroscopy (NEXAS) comparisons for the O K1 edges of TiO2 and optimized Ti Si oxynitride alloys provides a significantly reduced average crystal field d-state splitting from 1.9 to 1.6eV, as well as decreased electron trapping, and is correlated with a four-fold coordination of Ti in the Ti Si oxynitride alloys. The flat band voltage shift with varying frequency from 10 kHz to 1MHz in these alloys is less than 12 mV and the compositional dependence of current-voltage characteristics on Si3N4 composition results in the lowest leakage current at a Si3N4 content of ~40 % with the smallest equivalent oxide thickness (EOT) as well. Based on these studies, Transition Metal (TM) Si oxynitride alloys are anticipated to yield EOT <1 nm for scaled CMOS devises.
Influences of Plasma Processed Interface Layers on Germanium MOS Devices with ALD Grown HfO2
Authors: Sugawara Takuya , Sreenivasan Raghavasimhan , Oshima Yasuhiro , McIntyre Paul C. 
Published: April 2011

AbstractGermanium and hafnium-dioxide (HfO2) stack structures' physical and electrical properties were studied based on the comparison of germanium and silicon based metal-oxide-semiconductor (MOS) capacitors' electrical properties. In germanium MOS capacitor with oxide/oxynitride interface layer, larger negative flat-band-voltage (Vfb) shift compared with silicon based MOS capacitors was observed. Secondary ion mass spectrum (SIMS) characteristics of HfO2-germanium stack structure with germanium oxynitride (GeON) interfacial layer showed germanium out diffusion into HfO2. These results indicate that the germanium out diffusion into HfO2 would be the origin of the germanium originated negative Vfb shift. Using Ta3N5 layer as a germanium passivation layer, reduced Vfb shift and negligible hysteresis were observed. These results suggest that the selection of passivation layer strongly influences the electrical properties of germanium based MOS devices.
Impact of Interfacial Nitridation of HfO2 High-k Gate Dielectric Stack on 4H-SiC
Authors: Mahapatra Rajat , Chakraborty Amit K. , Tappin Peter , Miao Bing , Horsfall Alton B. , Chattopadhyay Sanatan , Wright Nick G. , Coleman Karl S. 
Published: April 2011

AbstractHfO2 films were grown on SiO2/4H-SiC and SiON/4H-SiC layers by evaporation of metallic Hf in an electron beam deposition system followed by thermal oxidation. X-ray photoelectron spectroscopy confirmed the formation of HfO2 films. There is no evidence of formation of hafnium silicide or carbon pile up at the surface as well as at the interfacial layer. Electrical measurements show the presence of fewer slow traps in the HfO2/SiON gate dielectric stack on 4H-SiC and comparable values of interface state density. The HfO2/SiON stack layer improves leakage current characteristics with a higher breakdown field and has better reliability under electrical stress.
Rashba Spin-Splitting and Spin Currents in GaN Heterojunctions
Authors: Weber Wolfgang , Seidl Simon , Golub Leonid E. , Danilov Sergey N. , Bel'kov Vasily V. , Ivchenko Eugenious L. , Prettl Wilhelm , Kvon Zee Don , Cho Hyun-Ick , Lee Jung-Hee , Ganichev Sergey D. 
Published: April 2011

AbstractGallium nitride is a potentially interesting material system for Spintronics since it is expected to become ferromagnetic with a Curie-temperature above room temperature if doped with manganese and long spin relaxation times are detected in this material.
Mobility of Charge Carriers in Dilute Magnetic Semiconductors
Authors: Foygel Michael G. , Niggemann James , Petukhov A. G. 
Published: April 2011

AbstractWe studied electrical transport in dilute magnetic semiconductors, which is determined by scattering of free carriers by localized magnetic moments. In our calculations of the scattering time and the mobility of the majority and minority-spin carriers we took into account both the effects of thermal spin fluctuations and of built-in spatial disorder of the magnetic atoms. These effects are responsible for the magnetic-field dependence of the mobility of the charge carriers. The application of the external magnetic field suppresses the thermodynamic spin fluctuations thus increasing the mobility. Simultaneously, depending on the type of the carriers and on parameters of the impurity potential, scattering by built-in spatial fluctuations of the atomic spins increases or decreases with the magnetic field. The latter effect is due to the change in the magnitude of the random local Zeeman splitting with the magnetic field. We discuss the role of the above effects on mobility and magnetoresistance of semiconductors where magnetic impurities are electrically active or neutral.
Structural Effects of Transition Metal Oxide Calcinations on Wurtzite Type Semiconductors That are Ferromagnetic at Room Temperature
Authors: Moeck Peter , Noice Lori , Li Chunfei , Gupta Amita , Erni Rolf , Browning Nigel D. , Rao K.V. 
Published: April 2011

AbstractGallium nitride powders and zinc oxide powders were each calcined with a few weight percent of copper oxide and/or magnesium oxide either in air or N2. Powder X-ray diffractometry, transmission electron microscopy, energy dispersive X-ray spectroscopy, and electron energy loss spectroscopy were performed in order to observe calcination induced structural effects on these wurtzite type semiconductors. We note that our earlier magnetic results on Cu doped GaN are qualitatively consistent with recent first principle calculations [Wu et al., Appl. Phys. Lett. 89 (2006) 62505].
Correlations Between Optical Transmission and Magnetic Properties of Doped and Undoped GaMnN
Authors: Mahros Amr M. , Luen M. O. , Emara A. , Berkman E. A. , Arkun F. E. , Zhang X. , Muth J. , El-Masry N. A. , Bedair S. M. 
Published: April 2011

AbstractFerromagnetism (FM) in GaMnN was found to be related to the position of the Fermi level relative to the Mn deep-level band. The location of the Fermi level can be altered by doping GaMnN with Si (n-type) and Mg (p-type) dopants, resulting in a ferromagnetic to paramagnetic transformation. We have found that this manipulation of the Fermi level also can affect the optical properties of GaMnN, GaMnN: Mg and GaMnN: Si. The major optical absorption bands were found either to be enhanced or diminished depending on the level and nature of the doping elements. Therefore, a correlation between optical properties and saturation magnetization of GaMnN can be established.
Interface Properties of PrxAl2-xO3 (x = 0 to 2) Dielectrics on TiN Studied by Synchrotron Radiation X-ray Photoelectron Spectroscopy
Authors: Lupina Grzegorz , Schroeder Thomas , Wenger Christian , Dabrowski Jarek , Lippert Gunther , Müssig Hans-Joachim 
Published: April 2011

AbstractExtending the scalability of deep trench capacitor dynamic random access memories requires introduction of a high-k dielectric-based storage capacitor structure. Pr-enriched Al2O3 dielectrics with TiN electrodes appear as a promising materials system for this application. Electrical measurements performed on this materials combination show, however, that achieving a very low capacitance equivalent thickness and low leakage current requires very careful control of the electrode/dielectric interface properties. In particular, formation of a parasitic interface layer has to be avoided. For this purpose, we carried out a systematic synchrotron radiation x-ray photoelectron spectroscopy study to non-destructively investigate the interface reactivity of the PrxAl2-xO3 (x = 0, 1, 2)dielectrics with TiN metal electrodes. The depth profiling study shows that the TiN substrate is covered with a native TiO2. Additionally, a thin interfacial Ti oxynitride layer is present between these compounds, resulting in a TiN/TiNO/TiO2 materials stack. Molecular beam deposition of Al2O3 onto substrates of this structure leads to a remarkable reduction of the native oxide. In contrast, in the same way deposited PrAlO3 and Pr2O3 dielectrics are significantly less reactive towards TiO2. As a consequence, the native TiON/TiO2 remains the main component of the interface layer in the TiN/PrAlO3 and TiN/Pr2O3 capacitor stacks. Such a configuration poses severe scalability problems to the Pr aluminate dielectrics.
Transport AC Losses of YBCO Coated Conductor Coils
Authors: Grilli Francesco , Ashworth Stephen P. 
Published: April 2011

AbstractCertain practical applications of YBCO coated conductors (CC) involve superconducting tapes wound in coils. In such a configuration the superconducting tape is arranged as closely packed turns, leading to an increase of the magnetic field generated by the current in the tapes and, consequently, a significant increase in the AC losses, with respect to an ‘isolated’ tape. In order to predict and reduce the refrigeration requirements of applications, it is therefore very important to be able to quantify the magnitude of such AC losses, both experimentally and by means of numerical calculations.
Robust Printing and Dispensing Solutions with Three Sigma Volumetric Control for 21st Century Manufacturing and Packaging
Authors: Li Bo , Clark Patrick Alan , Hail Kenneth 
Published: April 2011

ABSTRACTThe trend for the electronics industry to develop more functional, smarter and more compact devices has stressed the traditional manufacturing and packaging processes including the printing/dispensing technology. The traditional printing technique (e.g. time-pressure needle dispensing, screen printing, pin transfer and jetting) each has their own disadvantages in terms of dimensionality, accuracy, repeatability, flexibility and consistency, which have become the bottle neck of the industry. Enabling tools and technologies are greatly needed for the manufacturing and packaging of highly integrated and complicated parts and assemblies. In this paper, nScrypt will present novel pumping technologies and innovative printing/dispensing solutions for 21st century manufacturing and packaging. nScrypt's novel pump and robust system can dispense with precise volume control for tens of picoliter resolution, accurately place or align within a few microns, conformably print on exaggerated surfaces of tens of centimeters, and are flexible with materials and patterns. Dispensing of micro lines, dots, three-dimensional structures and conformal printing will be presented. This process has a wide range of applications including, but not limited to, conductors, resistors, optics, adhesives, sealants, frit, solders, encapsulates, wire bonding, underfilling, flip-chip bumping and 3-D structures.
Hot Embossing of Electron Beam Generated Structures in Polypropylene
Authors: Leech Patrick W. 
Published: April 2011

ABSTRACTThe hot embossing of electron beam generated structures with linewidths 0.35-3.25 μm has been examined in biaxially-oriented polypropylene (BOPP). The individual test elements consisted of pixels of 30 x 30 μm with a specific configuration of symbols and lettering. The embossing of these features has been performed as a function of temperature (80-140 °C) and applied pressure (2-20 kPa). Significant increases in both embossed depth and sidewall angle was evident over the temperature range 100 to 130 °C with a leveling off at higher temperatures attributed to the onset of a regime of viscous liquid flow. At temperatures within this regime, a critical level of pressure was required to fill the mold features. Accurate embossing of medium and coarse lettering (0.50-0.65 μm linewidth) and geometric symbols (1.25-3.25 μm linewidth) has been demonstrated at a temperature of 130 °C and an applied pressure of 13 kPa. The finest lettering (0.35 μm linewidth) was incompletely embossed under these conditions.
Photoinduced Charge Transfer at Hybrid Semiconductor Interfaces
Authors: Cabanillas-Gonzalez Juan , Egelhaaf Hans Joachim , Lanzani Guglielmo , Brambilla Alberto , Duò Lamberto , Finazzi Marco , Ciccacci Franco 
Published: April 2011

AbstractWe monitor in real time photoinduced charge injection at the interface between a fluorinated copper phthalocyanine layer (CuPcF16) deposited by thermal evaporation on top of a p - doped GaAs (100) wafer. Literature data on the electron affinity of CuPcF16 (5.2 eV respect to vacuum level) combined with photoemission measurements indicates an energy offset of 1.1 eV for the GaAs conduction band respect to the CuPcF16 LUMO level. This suggests that charge transfer at the organic - inorganic interface is feasible. We study bilayers of GaAs and CuPcF16 thin films (25 nm) by pump - probe spectroscopy with 200 fs time resolution. Pump photons at 780 nm excites the CuPcF16 layer whereas probe photons in the visible range, reflected by the GaAs surface, monitor induced changes at the interface. We observe a strong photoinduced absorption band centered around 560 nm which appears during the pulse duration, shows a build-up dynamics and persists beyond 0.2 ns. This band cannot be attributed to single material contribution, as demonstrated by test experiments with single layers. By applying steady state (CW) electromodulated spectroscopy we identify charge state absorption in CuPcF16 in the same spectral region as the photoinduced absorption band. We thus assign our transient dynamics to formation of CuPcF16 ions at the interface, following charge injection. On account of the rapid charge formation we identify this system as a potential candidate for the fabrication of hybrid photodiodes.
Engulfment of Protruding Micro-Nails Fabricated on Chip Surface by Cultured Neurons Improve Their Adhesion to The Electronic Device
Authors: Spira Micha E. , Kamber Dotan , Dormann Ada , Cohen Ariel , Bartic Carmen , Borghs Gustaaf , Shabthai Keren , Langedijk J.P.M. Langedijk , Yitzchaik Shlomo , Shappir Josef. 
Published: April 2011

AbstractOne of the major problems in assembling efficient neuro-electronic hybrids systems is the low electrical coupling between the components. This is mainly due to the low resistance, extracellular cleft formed between the cell's plasma membrane and the substrate to which it adhere. This cleft shunts the current generated by the neuron, or the device and thus reduces the signal to noise ratio. To increase the clefts electrical resistance we fabricated gold micronails that protrude from the transistor gate surface. The micronails were functionalized by phagocytosis facilitating peptides. Cultured neurons readily engulf the functionalized micronails forming tight physical contact between the cells and the surface of the device
Characterization of a Micro Capillary Zone Electrophoresis System With Integrated Amorphous Silicon Based Optical Detectors
Authors: Schöler Lars , Seibel Konstantin , Schäfer Heiko , Püschl René Johannes , Wenclawiak Bernd , Böhm Markus 
Published: April 2011

AbstractApplication specific Lab-on-Microchips (ALMs) making use of the combination of complex microfluidic networks with microelectronic circuits and micro optical components allow the realization of miniaturized application specific biological and chemical processing and analysis devices. Fluorescence sensing is one of the most widely used detection technologies, e.g. for DNA fluorescence labelling in Micro Capillary Electrophoresis (µCE) due to its superior sensitivity and specificity. Unfortunately, commercially available fluorescence sensing systems are physically very large, non portable, expensive and constrain the analysis in portable diagnostic and medical care. Integrated semiconductor optoelectronic devices can provide a portable, parallel and inexpensive solution for on chip fluorescence sensing.Most µCE applications working in the spectral range of visible light. For the integration of optical detection components a photon energy range of 1.6 eV - 3.1 eV is of interest. The a-Si:H technology accomplished due to the low dark current and high absorption coefficient against to crystalline silicon the requirements in that spectral range. In this paper we combine a:Si-H photo sensors with a fluidic micro system to detect the fluorescence of a rhodamine analyte mixture. The analyte mixture was excited by light with a wavelength in the range of λEx = 450 - 490 nm. The a-Si:H detector reveals a low dark current density on the order of 10-10 A/cm2 and a sufficient dynamic range of ∼100 dB under illumination of ∼1000 lx as a function of bias voltage. The measurement shows that the movement of the rhodamine plug in the microchannel causes a significant rise in the pin-diode photo current, which correlates to the evaluated signal of a microscope image detector. The photo current difference for excitation and additional fluorescence amounts to 2.4 µA.
Development of a Lab-on-a-Chip for the Characterization of Human Cells
Authors: Ertl Peter , Richter Lukas , Mak Andy , Stepper Christoph , Kast Michael , Brückl Hubert 
Published: April 2011

AbstractMicrofabricated biochips are developed to continuously monitor cellular phenotype dynamics in a non-invasive manner. In the presented work we describe the novel combination of contact-less micro-dielectric sensors and microfluidics for quantitative cell analysis. The cell chip consists of a polymeric fluidic (PDMS) system bonded to a glass wafer containing the electrodes while temperature and fluid flow are controlled by external heating and pumping stations. Additionally, the cell chip contains an integrated reference arm providing a low-noise detection environment by eliminating background signals and interferences. The high-density interdigitated capacitors (µIDC) are designed to monitor living cells in a space of approximately 10 nL volume by controlling critical electrode characteristics, such as size, shape and passivation composition as well as thickness. The integrated µIDCs are isolated by a 300 nm multi-passivation layer of defined dielectric property and provide non-invasive, stable, robust and non-drifting measurement conditions. The performance of this detector is evaluated using various bacterial, yeast and mammalian cells.
Polarized Silver Nanoparticles by Ionic Liquid and Its Application to Facilitated Olefin Transport Membranes
Authors: Kang Sang Wook , Char Kookheon , Kang Yong Soo 
Published: April 2011

AbstractThe BMIM+NO3-/Ag metal nanocomposite membranes were utilized for separation of propylene/propane mixtures. The selectivity of propylene/propane and the mixed gas permeance increased to 10 and 1.3 GPU, respectively. It is anticipated that the interactions between NO3- of BMIM+NO3- and the surface of silver nanoparticles causes the Ag surface to be partially positively charged, resulting in the reversible complexation with propylene and consequently facilitated propylene transport. The surface positive charge was confirmed from the increase in the binding energy of the d5/2 orbital of the silver nanoparticles by x-ray photoelectron spectroscopy. It increased from 368.26 for the neat silver nanoparticles to 368.47 eV for BMIM+NO3-/Ag metal composite. The positively charged surface of silver nanoparticles can be utilized as a new durable olefin carrier for facilitated transport.
New Organo-Inorganic Materials for Water Contaminants Remediation
Authors: Ortiz-Polo Araceli , Richards-Uribe Rosa M , Otazo-Sánchez Elena M , Prieto-García Francisco , Hernández-Ávila Juan , Acevedo-Sandoval Otilio , Gordillo-Martínez Alberto 
Published: April 2011

ABSTRACTMaterials with high specific surface areas such as pillared clays and zeolites have been studied and can be used to remediate contaminated water. Chemical functionality or compounds can be anchored or attached to the surface of a low-cost material used as a support matrix. This work studied the suitability of inexpensive natural mineral soils to decontaminate waste water from mine and metallurgic industries. Native mineral soils were also impregnated with commercial 1,3 diphenyltiourea (DFT) to improve retention of heavy metal ions. The natural mineral soils were from Hidalgo State in Mexico: white marble (calcite: CaCO3), volcanic gravels named “red and black tezontles” (anorthite matrix: CaO.Al2O3.(SiO2)2with FexOyand PbxOy), green zeolites (mordenite: Na2CaK2.OAl2O3.10SiO2.7H2O) and kaolin (kaolinite: Al2O3(SiO2)2.H2O). They were ground and sieved. The 50 mesh fraction was studied by Raman and FTIR spectroscopy, X ray powder diffraction and scanning electronic microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDX). From these solids new hybrid materials were prepared by impregnation with DFT in ethanolic solutions. Products were characterized and compared with untreated materials. Tezontles, zeolites and kaolinite showed the best impregnation levels. In their surfaces, grown DFT crystals showed different structures. The obtained hybrid solids were tested using several metallic ion solutions: Mn(II), Ni(II), Co(II), Cd(II), Hg(II), Pb(II), Cu(II) and Zn(II). The metallic adducts were analyzed and the adsorption capacity is discussed. The materials showed high remotion percentages for all metal ions and low Hg(II), Pb(II) and Cd(II) final concentrations. They have good potential for use in remediation of contaminated water with highly toxic metal ions. The metallic adducts were characterized by FTIR and Raman spectroscopy, as well as SEM/EDX analysis. However, all of mentioned methods were not useful for detection of impregnated DFT nor adsorbed or coordinated metallic ions on the supporting materials. Only the SEM/EDX method was found to be suitable for analysis.