bluuebunny/crossref_metadata_2025_split huggingface dataset:
Failure Analysis Using Voltage Contrast and Ebic
Authors: Rice Larry , Chen Wei 
Published: April 2011

AbstractAs ULSI device critical dimensions continue to shrink to submicron sizes, electron microscopy techniques such as electron beam induced current (EBIC) and voltage contrast are finding more applications towards pinpointing failure sites for subsequent cross sectioning or deprocessing. In addition to the traditional use of EBIC for junction delineation, EBIC has been applied to locate leakage sites in capacitor structures and silicon-on-insulator (SOI) devices as well. Similarly, voltage contrast has been applied to identify single or multiple opens in via chains which consist of thousands of vias. In addition to a brief revisit of the basic principles of EBIC and voltage contrast, focus will be placed on the application of EBIC and voltage contrast in failure analysis of semiconductor devices. Examples of using voltage contrast combined with precision cross section focused ion beam (XFIB) for identifying the failure mechanism of 0.8μm vias will be presented. Also, the use of EBIC for identifying leakage sites in SOI and bipolar devices and subsequent FIB/scanning electron microscopy (SEM) analysis will be presented.
Energy-Filtered Transmission Electron Microscopy of Multilayers in Semiconductors
Authors: Liu C. P. , Boothroyd C. B. , Humphreys C. J. 
Published: April 2011

AbstractKnowledge about compositional profiles on an atomic scale is important for semiconductor multilayers. In this paper, we attempt to quantify the Ti atomic fraction in a TixAll–xN multilayer and the total As concentrations in As δ-doped layers using energy-filtered imaging. These two materials represent materials where the characteristic energy loss edges are located in widely different energy losses with the L edge of Ti being above 450eV and that of As around 1350eV. The accuracy of the Ti atomic fraction in TixAll–xN is found to be around 10at% for specimens of uniform thickness made by focused ion beam milling, whereas the resolution and As concentration for the As containing δ-layer is found to be dominated by the signal to noise ratio.
Installing and Operating Fegtem's
Authors: Hetherington C. J. D. , Cullis A. G. , Walker S. , Turner J. , Nelson E.C. , O'Keefe M.A. 
Published: April 2011

AbstractThe latest transmission electron microscopes with field emission guns and imaging filters now provide much of the microanalysis and imaging necessary in applications such as ULSI device development. The installation and operating environment of the instruments are critical to their successful operation. Information from two such installations is presented here, one in a purpose built facility and the other in an existing building. Ground vibration, acoustic noise, stray electromagnetic fields, air flow and temperature variation are considered, and the measures implemented to achieve desirable levels of each parameter are discussed. The physical layout of an installation is also shown.
Relaxation of Metamorphic III-V Heterostructures Studied by Digital Processing of HREM Images
Authors: Rocher André , Snoeck Etienne , Goldstein Léon , Jacquet Joël , Fortin Catherine 
Published: April 2011

AbstractThe crystalline structure of metamorphic heterostructures grown by epitaxy has been studied by digital processing of High Resolution Electron Microscopy (HREM) images. Two systems have been investigated: the GaSb/(001)GaAs, known to be fully relaxed by a perfect Lomer dislocation network and the GaAs/(001)InP relaxed by partial and 60° dislocations randomly distributed. A transition zone can be defined between the perfect substrate and the relaxed epitaxial layer: its thickness is less than 20Å in GaSb/GaAs and more than 80Å in GaAs/InP. These results indicate that the misfit dislocations are only one of the elements involved in the relaxation of misfit stress.
HRTEM Study of Structure and Evolution of Highly Mismatched Heteroepitaxial Interface, GaSe/GaAs(100)
Authors: Dai Z.R. , Chegwidden S. R. , Ohuchi F. S. 
Published: April 2011

AbstractThe microstructural evolution of the GaSe/GaAs(100) thin film system was characterized by high resolution transmission electron microscopy (HRTEM). The relationship of crystallographic orientation between the GaSe thin film and the GaAs substrate is [011]GaAs ‖ [1100]GaSe/(100)GaAs ‖ (0001)GaSe, with the dominant polytype for the GaSe thin film being a γ-type which has a 3R-rhombohedral structure with R3m space group. An intermediate layer was observed between the GaAs substrate and the GaSe thin film, with a structure distinct from that of either GaAs or GaSe. The result of a fast Fourier transform (FFT) of the lattice image corresponding to the intermediate layer indicated that its crystal structure was associated with that of α-Ga2Se3. A new vacancy ordered structural model of β-Ga2Se3 was suggested.
Application of Tem on Sub-Half Micron Semiconductor Devices
Authors: Zhang Hong 
Published: April 2011

AbstractApplication of transmission electron microscopy on sub-half micron devices has been illustrated in terms of process evaluation and failure analysis. For process evaluation, it is emphasized that a large number of features need to be examined in order to have reliable conclusions about the processes, while for failure analysis, the goal is to pin-point a single process step causing failure or a single source introducing the particle defect.
Growth And Structure Of Nanometric Iron Oxide Films
Authors: Guiot E. , Gota S. , Henriot M. , Gautier-Soyer M. , Lefebvre S. 
Published: April 2011

ABSTRACTNanometric films of iron oxides (Fe3O4, α and γ Fe2O3) of high crystalline order and purity are epitaxially grown on α-A12O3(0001) by atomic oxygen assisted MBE. A complete characterization of the films structure has been performed by in situ LEED and RHEED, and ex situ GIXRD using synchrotron radiation. The films grown at room temperature and post annealed at 400°C and 700°C (po2=10−6 Torr) are respectively metastable γ-Fe2O3 (111) and α-Fe2O3 (0001). For a substrate temperature of 450°C during growth, Fe3O4 (111) is directly obtained. GIXRD shows an in-plane expansion of the films, which decreases with thickness (0.8 and 0.2% for film thickness of 20 and 80 Å, respectively).
Degree of Crystallinity and Strain in B4C and SiC Thin Films as a Function of Processing Conditions
Authors: Hershberger J. , Rek Z. U. , Kustas F. , Yalisove S. M. , Bilello J. C. 
Published: April 2011

ABSTRACTAmorphous and crystalline content in sputtered B4C and SiC thin films has been analyzed by synchrotron grazing incidence x-ray scattering (GIXS). GIXS provided quantitative information on the average structure while TEM was used to find inhomogeneities such as small volume fraction phases. GIXS results were compared to simulations to determine average particle size or bond length for crystalline or amorphous phases respectively. In this work, we compared results from films deposited with, and without, an RF bias applied to the substrate during deposition. Results indicated that SiC can be described as strained polycrystalline material with particle size of approximately 13 Å for biased samples and 9Å for unbiased samples. Boron carbide deposited without bias was completely crystalline with a particle size of approximately 30 Å, while the data suggested that B4C deposited with bias is amorphous. The scattering from the biased materials was Fourier transformed to yield radial distribution functions (RDF). This provided nearest neighbor distances, and it was demonstrated that the technique can be used to determine full three-dimensional strain tensors in amorphous thin films.
Direct Correlation of Solar Cell Performance with Metal Impurity Distributions in Polycrystalline Silicon using Synchrotron-Based X-ray Analysis
Authors: McHugo S. A. , Thompson A. C. , Lamble G. , MacDowell A. , Celestre R. , Padmore H. , Imaizumi M. , Yamaguchi M. , Perichaud I. , Martinuzzi S. , Werner M. , Rinio M. , Moller H. J. , Sopori B. , Hieslmair H. , Flink C. , Istratov A. , Weber E. R. 
Published: April 2011

ABSTRACTThe work presented here directly measures metal impurity distributions and their chemical state in as-grown and fully processed polycrystalline silicon used for terrestrial-based solar cells. The goal was to determine if a correlation exists between poorly performing regions of solar cells and metal impurity distributions as well as to ascertain the chemical state of the impurities. Synchrotron-based x-ray fluorescence mapping and x-ray absorption spectroscopy, both with a spatial resolution of lμm, were used to measure impurity distributions and chemical state, respectively, in poorly performing regions of polycrystalline silicon. The Light Beam Induced Current method was used to measure minority carrier recombination in the material in order to identify poor performance regions. We have detected iron, chromium, nickel, gold and copper impurity precipitates and we have recognized a direct correlation between impurity distributions and poor performing regions in both as-grown and fully processed material. Furthermore, from x-ray absorption studies, we have initial results, indicating that the Fe in this material is in oxide form, not FeSi2,. These results provide a fundamental understanding into the efficiency-limiting factors of polycrystalline silicon solar cells as well as yielding insight for methods of solar cell improvement.
Amorphous Semiconductor Sample Preparation For Transmission Exafs Measurements
Authors: Ridgway M. C. , Glover C. J. , Tan H. H , Clark A. , Karouta F. , Foran G. J , Lee T. W. , Moon Y. , Yoon E. , Hansen J. L. , Nylandsted-Larsen A. , Clerc C. , Chaumont J. 
Published: April 2011

ABSTRACTA novel methodology has been developed for the preparation of amorphous semiconductor samples for use in transmission extended x-ray absorption fine structure (EXAFS) measurements. Epitaxial heterostructures were fabricated by metal organic chemical vapour deposition (group III-Vs) or molecular beam epitaxy (group IVs). An epitaxial layer of ∼2 μm thickness was separated from the underlying substrate by selective chemical etching of an intermediate sacrificial layer. Ion implantation was utilised to amorphise the epitaxial layer either before or after selective chemical etching. The resulting samples were both stoichiometric and homogeneous in contrast to those produced by conventional techniques. The fabrication of amorphous GaAs, InP, In0.53Ga0.47As and SixGe1-x samples is described. Furthermore, EXAFS measurements comparing both fluorescence and transmission detection, and crystalline and amorphised GaAs, are shown.
Synchrotron Radiation Hard X-Ray Microprobe by Multilayer Fresnel Zone Plate
Authors: Tamura S. , Ohtani K. , Yasumoto M. , Murali K. , Kamuo N. , Kihara H. , Yoshida K. , Suzuki Y. 
Published: April 2011

ABSTRACTA hard X-ray microbeam with submicrometer spot size from synchrotron radiation (SR) sources is expected to add a new dimension to various X-ray analysis methods. A Fresnel zone plate (FZP) is one of the promising focusing elements for X-rays. In order to develop high performance multilayer FZP for use in the hard X-ray region, Cu/Al concentric multilayers were fabricated by use of a DC sputtering deposition process. Lower Ar gas pressure or higher rotating speed of a wire substrate has been effective in forming smoother multilayer interfaces. From a focusing test of the Cu/Al FZP (100-zones) by the SR (λ= 0.154nm), microbeams of 1.5 μm φ and 0.8 μm φ have been achieved for the first- and third-order focal beams, respectively.
Temperature-Driven Oxidation Behavior of Pure Iron Surface Investigated by Time-Resolved EXAFS Measurements
Authors: Doh S. J. , Lee J. M. , Noh D. Y. , Je J. H. 
Published: April 2011

ABSTRACTThe surface-front oxidation mechanism of iron was investigated by time-resolved, glancingangle Fe K-edge fluorescence EXAFS measurements at various oxidation temperatures of 200-700 C. The glancing angle was chosen according to the depth of the oxide layer, roughly 1500-2000A. The oxidation behavior under rapid heating(up to 600°C within 10 minutes) was compared with the slowly heated oxidation process using the Quick-EXAFS measurements. In the slowly heated process, Fe3O4 was the dominating phase at a relatively low temperature (300-400 C) initially. However, at a relatively high temperature (above 600°C), the Fe2O3 and FeO crystalline phases are gradually enriched as the successive oxidation process involving intrusive oxygen proceeded. Remarkably under a prolonged heat treatment above 600°C, the stable FeO phase that exists in a deep-lying interface structure and Fe2O3 phase eventually dominates the thick front-surface structure. In a quickly heated process, however, Fe3O4 phase is less dominating, which is contradictory to the commonly accepted oxidation models. The EXAFS results are discussed in conjunction with the x-ray diffraction features under the same heat treatment conditions.
Novel Method for Controlling Nano Thin Coatings on Particulate Materials
Authors: Fitz-Gerald J. , Pennycook S. , Gao H. , Krishnamoorthy V. , Marcinka J. , Glenn W. , Singh R.K. 
Published: April 2011

AbstractParticulate coatings have wide ranging applications in several new technologies such as flat-panel displays, sintering of advanced ceramics, rechargeable batteries, etc. In this paper, we show the feasibility of the pulsed laser ablation technique to make very thin, uniformly distributed and discrete coatings in particulate systems so that the properties of the core particles can be suitably modified. Presently, laser ablation techniques have been primarily applied to deposit thin films on flat substrate materials. To deposit discontinuous particulate coatings, the laser induced plume from the target comes in contact with an agitated bed of core particles. The pressure and nature of the background gas (inert or active) controls the cluster size of the nano particles in the laser plume. Experiments were conducted for laser deposition of Ag nano particles on Al2O3 and SiO2 core particles by pulsed excimer laser (wavelength = 248 nm and pulse duration = 25 nanosecond) irradiation of a Ag sputtering target The surface coverage and coating uniformities of the film were found to depend on the synthesis parameters (energy density, # laser pulses, gas pressure backfill gas, molecular weight) as well as the residence time of the core particles in the plume regime. The films were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), wavelength dispersive x-ray analysis (WDX), scanning transmission electron microscopy (STEM), and x-ray photoelectron spectroscopy (XPS).
Thin Film Growth using Ablation of Ceramics with a Lina-Spark™ Atomizer
Authors: Hourlet R. , Vacassy R. , Hofmann H. , Vogel W. 
Published: April 2011

AbstractA laser spark atomizer (LINA-SPARK™), LSA, has been used for preparing powder particles from SnO2, Al2O3 and ZrO2 ceramic specimen. It is shown that this technique can be used for preparing thin films by direct deposition on a substrate. The as-prepared powder can also be redispersed and deposited using ultrasonic nebulization (Pyrosol) deposition. The latter approach is especially suited for deposition of controlled-size and multicomponent thin films.The coupling of the LSA to an induced coupled plasma (ICP) emission spectrometer is also discussed and compared with laser ablation. Generally powder particles produced from LSA present a narrower size distribution as powders prepared by laser ablation. As a result, the quantitative elemental analysis of solids are improved with full benefit of the sensitivity and detection limits of the ICP are lowered.
Automatic Control and Real-Time Monitoring of Laser Cleaning and Laser Ablation
Authors: Lu Y.F. , Meng M. , Hong M.H. , Low T.S. , Chan D.S.H. 
Published: April 2011

AbstractClosed-loop control and real-time monitoring of pulsed excimer laser cleaning and ablation have been realised by software and hardware design and development. The audible acoustic wave generated during excimer laser surface cleaning and ablation has been used as the feedback signal for the automatic control system of laser-surface interaction. Man–machine interface for laser operation and acoustic monitoring has been developed with LabVIEW 4.1 under Windows 95 environment. This system has been used to control and monitor laser cleaning and ablation processes in real-time and proven to successfully meet the requirements in our study. By database exchange, this automatic control system can also be applied to control drilling and materials removing.
Preparation of PZT/YBCO/YAIO Heterostructure Thin Films by KrF Excimer Laser Ablation
Authors: Ebihara Kenji , Kurogi Hiromnitsu , Yamagata Yukihiko , Ikegami Tomoaki , Grishin Alexander M. 
Published: April 2011

AbstractThe perovskite oxide YBa2Cu3O7-x (YBCO) and Pb(ZrxTi1-x)O3 (PZT) thin films have been deposited for superconducting-ferroelectric devices. KrF excimer laser ablation technique was used at the deposition conditions of 200-600mTorr O2, 2-3J/cm2 and 5-10 Hz operation frequency. Heterostructures of PZT-YBCO-YAlO3:Nd show the zero resistivity critical temperature of 82K and excellent ferroelectric properties of remnant polarization 32 μC/cm2, coercive force of 80kV/cm and dielectric constant 800. Cycling fatigue characteristics and leakage current are also discussed.
Mesoscopic Model for The Laser-Target Interaction
Authors: Ribeiro R. Mendes , Ramos Marta M.D. , Stoneham A.M. 
Published: April 2011

AbstractWe have developed a mesoscopic model for the study of pulsed laser ablation of transparent granular ceramics. The model enables the understanding of several features that happen at the surface of a transparent target and which play an important role in the evolution of the evaporation process.The results show that electron emission happens early, much before atom evaporation. High defect concentration regions (including grain boundaries, surface) are crucial for energy absorption. The model also predicts the generation of high intensity electric fields in places with high defect concentration, such as grain boundaries. Low fluences should have selective species removal, but higher fluences should give congruent removal.The dependence of the density of generated electrons, the evaporated species and energy on the material properties is included.
Laser Ablated CuCo Thin Films Exhibiting Controlled Anisotropic Giant Magnetoresistance
Authors: Madurga Vicente , Vergara J. , Ortega R.J. , Rao K.V. 
Published: April 2011

AbstractControlled microstructured thin films with nominal composition Cu95Co5 have been deposited on glass substrates by pulsed laser ablation at room temperature, in vacuum, for different target speed rotation. Atomic Force Microscopy, AFM, studies have shown a surface roughness not higher than 0.5 nm, for the as-deposited samples, which do not exhibit magnetoresistive, MR, behaviour. X-ray diffraction analysis show broad diffraction peaks, slightly shifted from pure Cu reflection peaks. After annealing, the samples show GMR. The AFM investigations reveal a surface roughness of =6.8 nm and =9.2 nm for the samples prepared with high and low target speed rotation, respectively. Furthermore the GMR data correspond to a strong anisotropic behaviour. A reversible MR is exhibited, for all the films, exclusively for perpendicular to the films plane applied magnetic field. Hysteretic MR behaviour is observed for any other direction: in the range of 70-80 deg., coercive MR fields from 0.17 Tesla to 0.05 Tesla are observed for the samples obtained at 10 rpm to 32 rpm respectively target speed rotation. These properties are discussed in terms of the shape anisotropy of magnetic Co nanoparticles.
Epitaxial Growth of YBa2CH3O7-δ Films on Rolling-Assisted Biaxially Textured Substrates (RABiTS) Produced by Pulsed Laser Ablation at Low Temperatures
Authors: Mathis J. E. , Goyal A. , Paranthaman M. , Specht E. D. , Kroeger D. M. , Lee D. F. , Martin P. M. 
Published: April 2011

AbstractEpitaxial YBa2Cu3O7-δ (YBCO) films were fabricated using laser ablation of YBCO onto rolling-assisted-biaxially-textured-substrates (RABiTS) at a temperature of 650°C. The configuration of the sample was YBCO/YSZ/CeO/Ni. The CeO2 and YSZ buffer layers were deposited using electron-beam evaporation and sputtering, respectively. Both of these techniques are considered to be industrially scalable. SEM images of the YBCO reveal a range of structures ranging from jumbled a-axis to dense c-axis morphologies depending upon the deposition conditions. X-ray θ-2θ scans show a similar c-axis dependence on the deposition conditions.
Pulsed Laser Deposition of Nd-Doped YBa2Cu3O7-x Films for Coated Conductor Applications
Authors: Varanasi C. , Biggers R.R. , Maartense I. , Dempsey D. , Peterson T.L. , Solomon J. , Mcdaniel J. , Kozlowski G. , Nekkanti R. , Oberly C.E. 
Published: April 2011

AbstractPulsed-laser ablation was used to deposit YBa2Cu3O7-x (YBCO) films on LaAlO3 and metallic substrates in an effort to understand and develop the processing of coated conductors with enhanced properties. Doping of YBCO films with Nd was utilized as an approach for increasing their flux pinning properties. Separate targets of Nd2O3 and YBCO were used instead of a pre-mixed Nd2O3-YBCO target. The critical current density (Jc) of the films was measured by whole body dc transport measurements and the transition temperature (Tc) by ac susceptibility. The composition vs. depth profiles of the films were obtained by Secondary Ion Mass Spectrometry. The critical current of a 5000 Å thick Nd-doped YBCO film on a LaAlO3 substrate was measured at 77 K and found to be 57 A (Jc = 1.1×106 A/cm2).
Pulsed Laser Deposition of Undoped and Ag-Doped Stacked Structures of YBaCuO for Bolometer Device Applications
Authors: Moxey D. E. , Kalyanaraman R. , Sharma A. , Narayan J. , Lee C. B. , Muth J. 
Published: April 2011

AbstractIn this paper we report our investigations related to the growth and characterization of superconducting stacked structures of YBaCuO(undoped)/YBaCuO(Ag-doped)/YSZ layers processed on Si(100) substrates. These films were deposited using pulsed laser deposition (PLD), and have been characterized using X-ray diffraction, scanning electron microscopy (SEM), and four probe electrical measurements. SIMS analysis has also been used to study the incorporation and diffusion of carbon in the superconducting layer. The focus of this work is on the issues of the role of silver in the superconductor, and its effects on the transport properties and microstructure of the structure. We also discuss the use of these films for bolometer device applications.
Study of Substrate Diffusion in Epitaxial N-Type CdSe Films Grown on GaAs (001) by Pulsed Laser Ablation
Authors: Park Jaewon , Rouleau Christopher M. , Lowndes Douglas H. 
Published: April 2011

AbstractN-type CdSe films with thicknesses of 470 - 630 nm were grown on (001) and 2°- miscut GaAs wafers by ArF (193 nm) pulsed laser ablation of stoichiometric CdSe targets at platen temperatures (Tp) of 250 - 425°C in vacuum and ambient Ar gas. Film-substrate interdiffusion was studied with Auger depth profiling, as well as energy dispersive x-ray fluorescent spectroscopy (EDS). Both techniques showed that extensive interdiffusion took place at the film-substrate interface for CdSe films grown at Tp≥ 355°C but was greatly reduced at Tp=250°C. Tilting the substrate to be approximately parallel to the ablation plume as well as decreasing the ambient gas pressure also reduced film-substrate interdiffusion.