bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved Characterization of high-k Degradation with Vacuum C-AFM
Authors: Polspoel Wouter , Vandervorst Wilfried , Aguilera Lidia , Porti Marc , Nafria Montserrat , Aymerich Xavier 
Published: April 2011

ABSTRACTLocal phenomena like trap assisted tunneling and oxide breakdown (BD) in new high-k gate oxides in advanced MOS devices hinder the acquisition of device requirements stated in the International Technology Roadmap for Semiconductors (ITRS). Conductive Atomic Force Microscopy (C-AFM) visualizes these local phenomena by measuring the local tunneling through the dielectric. In the first part of this work we show that the physical composition of surface protrusions, that are produced at sites electrically stressed with C-AFM and that distort the electrical measurements, is oxidized Si. In the second part, we illustrate that C-AFM measurements become more reliable in high vacuum (1e−5torr) as surface (oxidized Si protrusions) and tip damage is reduced. Finally, we illustrate good agreement between conventional macroscopic electrical measurements and nanometer-scale C-AFM measurements on normal and gate – removed high-k capacitors, respectively. Moreover, to illustrate the strength of the local tunneling technique, we show the possibility of locating BD spots on a high-k capacitor.
The Road To Flexible Mems Integration
Authors: Witvrouw Ann 
Published: April 2011

ABSTRACTThis paper first discusses the reasons for choosing CMOS-MEMS integration, in particular integration by poly-SiGe processing above CMOS. Next the current state-of-the-art for poly-SiGe MEMS integration and the needs for the future will be addressed. Market trends are translated into two roadmaps for MEMS integration. The first roadmap is based on existing poly-SiGe deposition processes at 400 − 450 ºC. The second roadmap explores processing techniques to lower the thermal budget and widen the application field of MEMS integration by using processing techniques such as metal-induced crystallization, laser annealing or self-assembly.
Effects of Sputtering Metal Deposition Parameters in the Photoresist used as a Sacrificial Layer in Micro-electromechanical System Devices
Authors: Molinero David 
Published: April 2011

ABSTRACTThe present letter describes a reliability study of the micro-electromechanical system fabrication with a photoresist layer used as sacrificial layer with an aluminum beam deposited by means of RF sputtering method. This work reports changes of the roughness and planarity of the sacrificial layer beneath the aluminum film following the sputtering deposition. Such changes may be attributed to the alteration of the photoresist properties due principally to the outgassing of hydrogen by decomposition of C-H bonds under argon plasma. A safe deposition parameters area was identified where the photoresist layer keeps its properties and may be used as sacrificial layer.
Microstructured Soft Glass Fibers for Advanced Fiber Lasers
Authors: Schulzgen Axel , Li Li , Zhu Xiushan , Suzuki Shigeru , Temyanko Valery L. , Albert Jacques , Peyghambarian Nasser 
Published: April 2011

ABSTRACTCombining novel highly-doped phosphate glasses and advanced fiber drawing techniques, we fabricated and tested single-frequency fiber lasers that generate powers of more than 2-W. We demonstrate enhanced performance employing active photonic crystal fiber compared to more conventional devices that are based on large core step-index fiber.Through the integration of phosphate glass fiber gratings and highly-doped active phosphate glass fiber, we improve on optical, thermal, and mechanical behavior of our compact fiber lasers. Powerful and widely tunable phosphate glass distributed fiber lasers are presented and the possibility of cascading several grating structure for multiple wavelength generation is demonstrated. We also present results on phase-locking and coherently combining the output of up to 37 fiber cores into a single, near-Gaussian laser beam. To achieve exclusive oscillation of the fundamental in-phase supermode, several all-fiber laser cavities have been designed, numerically analyzed, fabricated, and tested. We will report on a 10-cm long monolithic all-fiber laser that emits more than 12-W of optical power and is based on combining the output of 19 active cores. All the cores are integrated within the same cladding and arranged in a two-dimensional isometric array.
Single Carrier Initiated Low Excess Noise Mid-Wavelength Infrared Avalanche Photodiode using InAs-GaSb Strained Layer Superlattice
Authors: Banerjee Koushik , Mallick Shubhrangshu , Ghosh Siddhartha , Plis Elena , Rodriguez Jean Baptiste , Krishna Sanjay , Grein Christoph 
Published: April 2011

ABSTRACTMid-wavelength infrared (MWIR) avalanche photodiodes (APDs) were fabricated using Indium Arsenide- Gallium Antimonide (InAs-GaSb) based strain layer superlattice (SLS) structures. They were engineered specifically to have either electron or hole dominated ionization. The gain characteristics and the excess noise factors were measured for both devices. The electron dominated p+-n−-n APD with a cut-off wavelength of 4.13 μm at 77 K had a maximum multiplication gain of 1800 measured at -20 V while that of the hole dominated n+-p--p structure with a cut-off wavelength of 4.98 μm at 77 K was 21.1 at -5 V at 77 K. Excess noise factors were measured between 1-1.2 up to a gain of 800 and between 1-1.18 up to a gain of 7 for electron and hole dominated APDs respectively.
ALADIN Doppler Wind Lidar and Related Programs at EADS Astrium
Authors: Morancais Didier , Fabre Frédéric , Toulemont Yves 
Published: April 2011

ABSTRACTThe Atmospheric Laser Doppler Instrument (ALADIN) is the payload of the ADM-AEOLUS mission, which will make direct measurements of global wind fields. It will determine the wind velocity component normal to the satellite velocity vector. The instrument is a direct detection Doppler Lidar operating in the UV, which will be the first of its kind in space.ALADIN is now in its final construction stage: the integration of the Flight Model is on-going. Most of the subsystems have been integrated; the payload performance and qualification test campaign will commence.This paper describes the ALADIN the development status and the results obtained at this stage. This regards the receiver performance, the telescope development and the challenges of the laser.The paper will also provide insights on the ATLID instrument design which is the backscatter lidar for the EarthCARE mission. This lidar program is starting its detailed design phase.The ALADIN and ATLID instruments are developed by EADS Astrium Satellites for the European Space Agency.
Geospatial Remote Sensing Using Advanced Sensor Systems
Authors: Vaseashta Ashok 
Published: April 2011

ABSTRACTRecently, various nanoscale materials, devices, and systems with remarkable properties have been developed, with numerous unique applications in chem.-bio sensors, nanophotonics, and nanobiotechnology. This presentation covers satellite and aerial remote sensing science and methodologies employing nanotechnology based advanced sensor systems to improve performance, resolutions, and security. Increased demand on monitoring, surveillance due to global war on terrorism, weather prediction, and environmental pollution detection and monitoring have necessitated geospatial sensing with high accuracy, speed, and authenticity. Plasmonic interactions on the nanoscale and nanophotonics have produced new phenomena and technologies surpassing the realms of possibilities with conventional photonics and electronics. These new technologies could include high spatial resolution near-field imaging, high efficiency information processing and transferring, high capacity optical data storage, flexible- and high contrast displays, and precise detection, control and manipulation of nanoscale devices and integrated systems. Elements utilizing refractive or diffractive surfaces have found applications in novel sub-wavelength nanostructures satellites. The nanophotonics structures coupled with lightweight structures and advanced nanotechnology based sensors have resulted in launching of nano-satellites by several countries. The use of nanophotonics in space through the combination of micro, nano, integrated and fibre-optic technologies is to reduce susceptibility of the system to EMI, reduction in the weight of the signal cables (< 1/20 of electrical), higher information transmission capacity (GHz), reduced weight and volume, opto-isolation of critical spacecraft subsystems, high speed optical processing of RF and microwave signals, low propagation loss, and enhanced security encryption capabilities. Carbon Nanotubes (CNTs) based field emission electron gun (FEG) employ low voltage for emission and are actively researched as cold cathode microwave generation devices. CNTs based composites provide light-weight and compact platform with mechanical and thermal robustness. Such satellite system can be placed in low Earth orbit (LEO) to medium Earth orbit (MEO) as multi-sensor satellite imagers with panchromatic, multi-spectral, area and hyper spectral sensors on a single focal plane array (FPA), to achieve medium to high resolution (2.5m to 15m) spatial sampling, wide swaths (up to 45km) and noise equivalent reflectance (NER) values of less than 0.5%. An evaluation of security risks, vulnerability, and strategies is presented for communications technologies used in gathering, processing, storing, and disseminating global environmental micro and nano sensors and satellite data.
Temperature Dependent Fluorescence of Nanocrystalline Ce-doped Garnets For Use as Thermographic Phosphors
Authors: Hansel Rachael , Allison Steve , Walker Greg 
Published: April 2011

ABSTRACTFour samples of (Y1−xCex)3(Al1−y Gay)5O12 (where x=0.01, 0.02 and y=0, 0.5) were synthesized via the simple, efficient combustion synthesis method in order to determine the effect of substituting Ga3+ for Al3+ on the temperature-dependent fluorescent lifetime. X-ray diffraction shows that the Ga-doped samples have longer lattice constants and transmission electron microscopy data show that each sample consists of nanocrystallites which have agglomerated in micron-sized particles. Photoluminescence data reveal that the addition of gallium into the YAG:Ce matrix induces a red shift in the absorption spectra and a blue-shift in the emission spectra. The laser-induced fluorescent lifetime was determined as a function of temperature over the range of 0-125°C using two different emission filters. Increasing the amount of dopant ultimately results in a decrease of the fluorescent lifetime. The quenching temperatures for the Ga-doped samples were lower than the samples without gallium. The results of this work show that combustion synthesis is viable method for making highly luminescent, nanocrystalline TGPs. In addition, these results show that the quenching temperature of YAG:Ce can be altered by substituting ions which alter the location of the charge transfer state and by changing the morphology of the sample.
Electrically Pumped Photonic Crystal Distributed Feedback Quantum Cascade Lasers
Authors: Razeghi Manijeh , Bai Yanbo , Slivken Steven , Zhang Wei 
Published: April 2011

ABSTRACTIn parallel with the effort to improve the efficiency of Quantum cascade lasers (QCL) for high power continuous wave (CW) operations, the peak power in pulsed mode operation can be easily scaled up with larger emitting volumes, i.e., processing QCLs into broad area lasers. However, as the emitter width increases, multi-mode operation happens due to poorer lateral mode distinguishability. By putting a two dimensional photonic crystal distributed feedback (PCDFB) layer evanescently coupled to the main optical mode, both longitudinal and lateral beam coherence can be greatly enhanced, which makes single mode operation possible for broad area devices. For PCDFB laser performance, the linewidth enhancement factor (LEF) plays an important role in controlling the optical coherence. Being intersubband devices, QCLs have an intrinsically small LEF, thus serves better candidates over interband lasers for PCDFB applications. We demonstrate electrically pumped, room temperature, single mode operation of photonic crystal distributed feedback quantum cascade lasers emitting at λ ∼ 4.75 μm. Ridge waveguides of 50 μm and 100 μm width were fabricated with both PCDFB and Fabry-Perot feedback mechanisms. The Fabry-Perot device has a broad emitting spectrum and a broad far-field character. The PCDFB devices have primarily a single spectral mode and a diffraction limited far field characteristic with a full angular width at half-maximum of 4.8 degrees and 2.4 degrees for the 50 μm and 100 μm ridge widths, respectively.
Propagation of high-frequency surface plasmons on gold
Authors: Peale Robert Edwin , Lopatiuk-Tirpak Olena , Cleary Justin W , Santos Samantha , Henderson John , Clark David , Chernyak Leonid , Winningham Thomas Andrew , Del Barco Enrique , Heinrich Helge , Buchwald Walter R 
Published: April 2011

ABSTRACTSurface plasmon propagation on gold over 0.1 – 1.6 micrometer distances for plasmon energies in the range 1.6 – 3.5 eV was characterized. Surface plasmons were excited by an electron beam near a grating milled in the gold. The spectra of out-coupled radiation reveal increasingly strong propagation losses as surface plasmon energy increases above 2.8 eV, but little effect in the range 1.6 – 2.8 eV. These results are in partial agreement with theoretical expectations.
Terahertz Metamaterials on Thin Silicon Nitride Membranes
Authors: Peralta Xomalin G. , Arrington C. L. , Williams J. D. , Strikwerda A. , Averitt R. D. , Padilla W. J. , O'Hara J. F. , Brener I. 
Published: April 2011

ABSTRACTThe terahertz (THz) region of the electromagnetic spectrum holds promise for spectroscopic imaging of illicit and hazardous materials, and chemical fingerprinting using moment of inertia vibrational transitions. Passive and active devices operating at THz frequencies are currently a challenge, and a promising emerging technology for such devices is optical metamaterials. In particular, a chem/bio sensing scheme based on the sensitivity of metamaterials to their dielectric environment has been proposed but may be limited due to the large concentration of electric flux in the substrate. In addition, there is an interest in fabricating 3D metamaterials, which is a challenge at these and shorter wavelengths due to fabrication constraints. In order to address both of these problems, we have developed a process to fabricate THz metamaterials on free-standing, 1 micron thick silicon nitride membranes. We will present THz transmission spectra and the corresponding simulation results for these metamaterials, comparing their performance with previously fabricated metamaterials on various thick substrates. Finally, we will present a scheme for implementing a 3D THz metamaterial based on stacking and possibly liftoff of these silicon nitride membranes.
A Novel Near-field Raman and White Light Imaging System for Nano Photonic and Plasmonic Studies
Authors: Shen Ze Xiang , Kasim J. , You Y. M. , Du C. L. 
Published: April 2011

AbstractWe show the approaches in achieving high resolution Raman and white light imaging. In Raman imaging, a dielectric microsphere is trapped by the incoming laser, which was focused onto the sample by the microsphere. The microsphere was also used to collect the scattered Raman signals. We show the capability of this method in imaging various types of samples, such as Si devices and gold nanopattern. This method is comparatively easier to perform, better repeatability, and stronger signal than the normal near-field Raman techniques. Besides the Raman imaging, we also show a far-field confocal white light reflection imaging system that can be used for the fast imaging and characterization of nanostructures. This system uses a xenon (Xe) lamp as the incident light source and tunable aperture to enhance the spatial resolution. It has a spatial resolution of around 370 nm at a wavelength of 590 nm. With our system, we can clearly resolve images of 300 nm nanoparticles arranged in 2D honeycomb arrays with a period of 500 nm. Localized surface plasmons (LSPs) of isolated single and dimer gold nanospheres were also studied and the resonance energy difference between their LSPs was extracted.
Materials and Components for Flexible and Stretchable Transducers
Authors: Bauer Siegfried 
Published: April 2011

ABSTRACTFlexible and stretchable electronic components are currently at the heart of macroelectronics research. Materials useful for such applications are based on entropy elastic soft matter, combined with energy elastic functional elements. Examples include functional materials for sensing pressure and temperature changes, such as ferroelectrets, ferroelectric polymers, and nanocomposites of ferroelectric polymers and piezoelectric ceramics. Components for making flexible or stretchable electronic components additionally require electronic circuitry based on amorphous silicon or on organic semiconductors. Progress in such electronic elements is rapid, state of the art are elements which can easily operate at low voltage levels of 1 V. Combined with functional materials, sensing elements for temperature and pressure changes are easily achieved, as demonstrated with a few working examples of paper thin microphones, optothermal switching elements and skin-like electronics. Entropy-elastic elastomers form the basis for actuating elements, outlined by examples based on self organized actuating structures. Such materials can be also made functional by design, enabling fully reversible stretchable sensing elements for temperature, pressure and other physical parameters.
Mechanical Integrity Study of Air Gap Structures Assisted by FE Simulations
Authors: Moreau Stephane , Gaillard Fré;déric , Barbé Jean-Charles , Gras Raphaël , Passemard Gérard , Torres Joaquin 
Published: April 2011

ABSTRACTIn this paper, mechanical reliability of “air gap” structures has been evaluated when a copper line is completely surrounded with air. Different Finite Element (FE) simulation models have been used on a 2-metal level structure to study the M2 copper line bow evolution as a function of its dimensions if complete air cavities are generated underneath (i.e. at via level). Design rules information may therefore be obtained to optimize “air gap” integration considering the 65 nm and 22 nm technology nodes. Thus, we not only highlight that M2 copper line can not collapse considering our failure criterion but that M2 bow variation may also be improved when a tensile SiCN capping layer is deposited on top of the structure. The influence of the interline spacing vs. M2 bow has also been studied and we show that its increase is a beneficial parameter for the air gap structure. In opposite, we demonstrate that buckling can occur when a compressive SiCN layer is used. Finally, we accurately predict the M2 bow variation for air gap structures of the 65 nm and 22 nm technology nodes, but stress and strain distribution can complementary be provided. Those results highlight interesting criteria for designers to build reliable air gap structures.
Moisture Adsorption in Plasma-Damaged Porous Low-k Dielectrics
Authors: Vinogradova Ekaterina , Smith Casey E , Mueller DW , McKerrow Andrew J , Reidy Rick 
Published: April 2011

ABSTRACTPlasma etch/ash processes can induce changes in low-k film surface/bulk chemistries and topographies resulting in increased water absorption, surface roughness, and metal intrusion. After ashing, the altered surface character of the low-k can impact wetting, adhesion, and, consequently, the resistance of subsequently deposited barrier layers. In this work, we describe the use of deuterium oxide as means of measuring moisture penetration into low-k films. Film chemistries have been monitored using grazing angle attenuated total reflectance (GATR) and transmission Fourier transform infrared spectroscopy (FTIR). To study moisture absorption in porous spin-on and CVD low-k films, unashed and ashed films have been exposed to D2O liquid and vapor treatments under “dry” nitrogen. The extent of D2O uptake, removal and exchange reactions has been studied using transmission and GATR FTIR methods because the D2O and O-D adsorption peaks are distinct from water and O-H as well as other low-k adsorptions. This method can be used to study Si-OH species because deuterium can exchange with hydrogen within silanols under ambient conditions while methyl groups are much less likely to exchange. Three different low-k films, a porous spin-on MSQ (k=2.2), a porous CVD (k=2.3), and an organosilicate glass (OSG, k=2.85) have been used. In FTIR spectra, unashed low-k films show minimal D2O adsorption. In MSQ hydrogen-ashed films, the data suggest the presence of deuterium oxide and O-D peaks. Further, D2O adsorption appears to be considerably higher for ashed films as would be expected due to the hydrophobicity of these films. In the CVD films, there does not appear to be as marked a difference. This method permits the introduction of a chemical “marker” into low-k wet and ambient processes allowing one to distinguish among adsorptions from different aqueous sources.
Off-Angular Deposition Compensation for PVD Selective Re-sputtering Process
Authors: Yang Hsien-Lung , Zhang Fuhong , Nelson Kim , Tseng Jennifer M. , Forster John , Sunddarrajan Arvind , Bhatnagar Ajay , Kumar Niranjan , Gopalraja Prabu 
Published: April 2011

ABSTRACTIn Copper back-end-of-line (BEOL), the “punchthru™ process” – removal of barrier material from via bottom during etch/re-sputter step, and gouging into the underlying Copper line - has been increasingly used in 65nm production for its superior reliability. However, with the adoption of porous low-k dielectric at 45nm node and beyond, the conventional punchthru process can cause physical damage to the porous dielectric, such as roughening of the trench bottom in dual damascene structures, micro-trenching in the bottom of single trenches, which may have reliability implications. This paper reported on the use of off-angular Tantalum neutral flux during the re-sputter process to improve the selectivity between the via and trench bottom in order to protect the trench bottom and via bevel, while still allowing sufficient gouging into the underlying Copper line. In addition, the plasma density and ion energy are adjusted to further optimize selectivity, and to eliminate any micro-trenching. Therefore, this paper demonstrated PVD high deposit/etch selectivity process based on transmission-electron microscopy (TEM) and studies of electrical test result. This approach has extended the PVD Tantalum barrier process to at least 32nm node.
Nanoindentation of Lead Free Solders for Harsh Environments
Authors: Marques Vitor Farinha , Grant Patrick , Johnston Colin 
Published: April 2011

ABSTRACTTo better understand the factors governing the reliability of lead free solders during severe excursions in temperature, the hardness and elastic modulus of the micro-phases formed in a Sn-Ag-Cu/Cu solder joint were characterized using nanoindentation at temperatures from 25 to 175°C. The creep behaviour of the different micro-phases was also studied as function of temperature. The hardness and elastic modulus of Cu6Sn5, Cu3Sn had a weak dependence on temperature, while primary Sn, eutectic regions and electroplated Cu hardness and modulus were sensitive to temperature. Creep studies indicated that intermetallic were more creep resistant than softer phases that readily underwent creep, the type and rate of which was shown to be strongly temperature dependent.