bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation of Rapid Thermal Processing Equipment and Processes
Authors: Lie Kun-Ho , Merchant Tushar P. , Jensen Klavs F.
Published: March 2011

We present finite element simulations of fluid flow, heat transfer, and chemical reactions in axisymmetric rapid thermal processing (RTP) configurations. A new approach to simulating radiation heat transfer between lamps, substrates, and system walls is described. The method accounts for multiple reflections and readily allows the inclusion of temperature, radiation wavelength, and materials specific emissivity parameters. The influence of system geometry, lamp power profile, substrate and wall emissivity parameters, and process gas flow upon RTP performance characteristics is illustrated through examples. Transient flow and heat transfer simulations are used to identify operating conditions where flow recirculations are avoided. The further use of physically based models in the design and optimization of RTP systems is discussed.
Three Dimensional Temperature Uniformity Modeling of a Rapid Thermal Processing Chamber
Authors: Knutson Karson L. , Campbell Stephen A. , Dunn Floyd
Published: March 2011

A 3-dimensional model of an industry standard Rapid Thermal Processing (RTP) chamber (AG Assoc. 4108 Heatpulse) has been created. The chamber consists of a quartz sleeve containing a 200mm wafer surrounded by a polysilicon thermal guard ring. The wafer is heated by tungsten filament lamps which are assumed to radiate according to Boltzmazi' gray-body model. Detailed radiation transfer among ∼4000 finite surfaces is considered as well as Navier-Stokes solution of an energy balance to determine chamber temperature distributions.

Experimental wafer temperature distributions have also been obtained using an 8 inch wafer imbedded with 17 thermocouples and from oxide growth measurements at 700 and 1100 Centigrade respectively. The model predictions are within 1% of the experimental data at both low and high temperatures with the only parameter being the lamp filament temperature. The model is used to demonstrate the ability to examine non-symmetric effects of varying specific chamber properties (i.e. lamp power output, wall reflectivity), as well as transient phenomena.
Boron Diffusion in Fluorine Preamorphized Silicon During Rapid Thermal Annealing
Authors: Kinoshita H. , Huang T. H. , Kwong D. L. , Bakeman P. E.
Published: March 2011

The effect of fluorine preamorphization on boron diffusion and activation during rapid thermal annealing (RTA) has been investigated. Compared with low energy B or BF2 implant into crystalline Si, F preamorphization suppressed the transient enhanced diffusion of B and increased dopant activation. Results show that the tail diffusion was absent, and thus the junction depth of the RTA annealed sample was established by the as-implanted B profile. Secondary ion mass spectroscopy and cross-sectional transmission electron micrograph results show F accumulation near the surface and at end-of-range defects. The interaction of F with defects is believed to reduce the B diffusion during RTA.
Investigation of Proximity Rtd for Submicron Junctions in Vlsi Si Devices
Authors: Zagozdzon-Wosik W. , Grabiec P. , Romero-Borja F. , Wood L. T. , Lux G.
Published: March 2011

Proximity rapid thermal diffusion is presented as a doping process for fabrication of very shallow junctions. The kinetics of Si doping with B, P and As is investigated using sheet resistance measurements, secondary ion mass spectroscopy and FTIR analyses. The efficiency of doping is affected by the dopant transport in the SOD which depends on the structure and composition of the SOD.
Rapid Thermal Annealing for Electrical Activation in The Fabrication of GaAs Mesfet
Authors: Choi S.W. , Yang J.W. , Koak B.H. , Cho K.I. , Park H.M.
Published: March 2011

Rapid thermal annealing (RTA) has been employed for the electrical activation of shallow n-channel layer by Si+ implantation in the fabrication of GaAs MESFET. To prevent considerable outdiffusion of gallium and arsenic from GaAs substrate during annealing, encapsulating layers such as SiNx and SiNx/SiO2 are deposited. The SiNx/SiO2 double dielectric encapsulant is shown to be more effective to improve the electrical activation. Depending on RTA temperature between 900 and 950°C, the maximum activation efficiency exhibits 77% at the implanted energy of 70 keV and the dose of 5x1012 cm−2. SIMS analyses show the reduction of the hydrogen contained in the silicon nitride and no outdiffusion of Ga and As during RTA. It also shows the sharp Si-profile after RTA at 950°C, 30 sec. The MESFET fabricated using activation with RTA provides better transconductance than that with furnace-annealed activation.
Poly-Si Thin Film Transistors Fabricated with Rapid Thermal Processing
Authors: Campo E. , Pedroviejo J.J. , Scheid E. , Bielle-Daspet D. , Messaoud A. Yahia , Sarrabayrouse G. , Martinez A.
Published: March 2011

In this work, we studied the rapid crystallization and the rapid tbermal oxidation of amorphous silicon films deposited at 465°C by low-pressure chemical vapor deposition (LPCVD) from disilane. The crystallization is well-controlled and the thermal bugdet is reduced compared to conventional processes. Results concerning the electrical and structural characteristics of poly-Si thin film transistors (TF7) are given. Furthermore, we obtained after plasma hydrogenation better mobilities in the case of rapid thermal processing (RTP) (μp-61 cm2/V.s, VT−8.3 V, subtbreshold slope−-0.8 V/decade, ION/IOFF− 1. 106 for p-type and μn-80 cm2/V.s, VT−3. 7 V, subthreshold slope−1.4 VWdecade, ION/IOFF−5.104 for n-type) compared to conventional processing performed at 600°C. The mobilities are improved by a factor of 2 to 3 despite the smaller grain size in the silicon films. We also showed a correlation between the optical absorption coefficient k (at 405nm) and the mobility wbicb appears not only dependent upon, the grain size but also upon the grain quality (grain boundaries and defects inside the grain).

This study shows that the structural and electrical properties of thin-films and oxides fabricated by RTP are at least as good as those obtained by conventional techniques.
Ultrathin Gate and Capacitor Dielectric Formation Using Single- Wafer Processing
Authors: Thakur R.P.S. , Ahmad A. , Ditali A. , Martin A. , Kermani A. , Galewski C. , Mcintosh R. , Legler K.
Published: March 2011

Various ultrathin gate and capacitor structures were formed in a single wafer, lamp heated, reduced pressure, cold wall CVD reactor. Sequential processes including in-situ rapid thermal cleaning, surface passivation, and dielectric formation for capacitor structures was achieved at reduced pressure using pure ammonia. Three types of dielectric films were fabricated: pure thermal oxide, oxynitride, and silicon nitride. The films were grown using pure dry oxygen, nitrous oxide, and silane/ammonia chemistries, respectively. Excellent uniformity across the wafer was observed for dielectric films of different thicknesses. The RTCVD-based films exhibited improved characteristics for leakage and device drive. The TDDB data indicates that the short and long term reliability of the gate and capacitor dielectric films formed with the singlewafer process was better than that obtained with furnace-grown films. Auger electron spectroscopy and ellipsometry techniques were used to correlate film composition with processing conditions. In this paper we present the growth kinetics, composition, and thickness uniformity data and the electrical results of single-wafer processing.
Self-Aligned Epitaxial Cosi2 Formation From Multilayer Co/Ti-Si(100) by a Two-Step Rta Process
Authors: Hong F. , Patnaik B.K. , Rozgonyi G.A. , Osburn C.M.
Published: March 2011

We have extended our recent work on nano-scale CoSi2 formation from Co/Ti(O)multilayers on Si(100) to a self-aligned epitaxial CoSi2 structure produced by a two-step RTA annealing process. Parallel oxide stripes/Si windows were produced on a 4-inch Si(100) wafer by thermal oxidation and patterning. Six layers of 20nm Co and 10nm Ti were deposited sequentially on the patterned wafers with Ti as the first layer. The wafers were then annealed at 550°C to 700°C in N2 using a lamp RTA system. XTEM and RBS showed that a 25nm CoSi layer formed at the interface after a 650°C, 60sec annealing. The unreacted layers above it and oxide were selectively removed leaving a residual amorphous layer and CoSi intact on the patterned Si substrates. A second annealing at 900'C for 10sec produced 20nm of epitaxial CoSi2 covered with an ∼10nm CoxTiy(O)Siz surface layer. The epitaxial CoSi2 layer was thermally stable up to 1000°C, had a resistivity of ∼20μΩ-cm, and consumed ∼300Å of Si, thereby satisfying the most stringent deep submicron device contact scaling requirements.
The Impact of Pre-Silicidation Heat Treatment and Dopant Effects on the Thermal Stability of Cosi2 Polycide During Rapid Thermal Annealing
Authors: Chen W. , Lin J. , Banerjee S. , Lee J.
Published: March 2011

The effects of heat treatment of polysilicon and amorphous Si films on their microstructure and thermal stability of polycides formed on these films have been studied. The number of grain boundaries decreases after pre-silicidation heat treatment in polysilicon due to grain growth but increases in amorphous Si due to nucleation. Since the thermal stability of CoSi2 polycide films was found to be closely related to the number of grain boundaries in the underlying silicon substrate, pre-silicidation heat treatments degrade the thermal stability of CoSi2 on as-deposited amorphous Si and improve the thermal stability of CoSi2 on asdeposited polysilicon. Doping does not have as pronounced an effects as substrate microstructure on CoSi21 polycide thermal stability, especially when dopants are introduced after silicidation by ion implantation.
Study of Chemical Interactions at the Stainless Steel / Polymer Interface by Infrared Spectroscopy
Authors: Thery S. , Mantel M. , Jacquet D.
Published: March 2011

The interfacial interaction of a thermoplastic copolymer ethylene-maleic anhydride with stainless steel has been studied by infrared spectroscopie techniques (FTIR) in order to improve the durability of steel/polymer association, by modifying formulation of polymer or surface treatment of stainless steel.

In order to be successful, an analytical methodology has been established. Interfacial chemical actions of maleic anhydride with stainless steel are simulated through thin layer of succinic anhydride on polished metal surface. FTIR spectroscopie (grazing angle) permit a direct access ot interphase for identifying new bounds between organic and metallic compounds.

Interaction of succinic anhydride with the polar OH groups of the oxidized metal surface follawed a reactional mechanism which can be described by two steps:

- opening of the anhydrid ring for reacting with adsorbed water and formation of acid group (-COOH),

- reaction of acid group with hydroxylic fraction of metal surface and formation of carboxylate anion (-COO-) groups.
Interfacial Bonding Mechanisms in Carbon Fiber/Pmr-15 Composites
Authors: Serrano A. M , Jangchud I. , Eby R. K. , Bowles K. J. , Jayne D. T.
Published: March 2011

X-ray photoelectron spectroscopy (XPS), tensiometric wetting, and atomic force microscopy (AFM) were used to investigate the surfaces of PAN based carbon fibers. Percent weighted dipole moments (%WDM) were computed from the deconvoluted core level carbon XPS peaks. Tensiometric wetting separated the polar and dispersive components of the fiber surface energies thus allowing the computation of % polar energies. AFM provided quantitative measurements of the fiber surface rugosities. Scanning electron microscopy (SEM) revealed adhesive interfacial fractures for PMR-15 (polyimide) composites of fibers with low %WDM and % polar energies; cohesive fractures for those with high %WDM and % polar energies. Increasing interlaminar shear strengths correlated with increasing %WDM and % polar energies. The fibers with higher %WDM also had rougher surfaces which probably expose more graphite basal plane dipole sites in addition to providing mechanical interlocking.
Microstructures of Chemically Polymerized Ultrathin Polypyrrole Films
Authors: Chu Xi , Chan Vivcent , Schmidt Lanny D. , Smyrl William H.
Published: March 2011

The microstructures of chemically polymerized polypyrrole 100 to 800 Å films were studied by transmission electron microscopy (TEM). The fibers are embedded in an amorphous matrix which forms a self-reinforced composite. The shape of the fibers ranged from thin rods to ellipsoids depending on the preparation conditions. The density and size of the fibers were affected by the polymerization time and the concentration ratio of pyrrole and oxidants. Polypyrrole fibers were aligned along the thin film plane and were randomly oriented in the plane. The two-dimensional orientation of the crystalline fibers produced strongly anisotropic electrical properties in the thin films. It has been found that by properly adjusting the polymerization condition, it is possible to obtain the polypyrrole conducting ultra thin films with improved mechanic and electric properties.
High Performance Processing for High Performance Polymers
Authors: Lusignea Richard , Blizard Kent , Rubin Leslie
Published: March 2011

High performance polymers require new processing technologies to achieve their full potential properties. The strength, stiffness, coefficient of thermal expansion, and barrier properties of LCPs and blends are strongly dependent on processing. The use of biaxial shear flow during extrusion, elongational strain after extrusion, electromagnetic field effects, and thermal treatment will be discussed with respect to LCP film processing. The effect of these conditions on the properties of films will be reviewed and applications for high barrier containers, electronic substrates and lightweight structures will be described.
Realization Of X-Ray Lithography Masks Based On Diamond Membranes
Authors: Ravet M. F. , Gicquel A. , Anger E. , Wang Z. Z. , Chen Y. , Rousseaux F.
Published: March 2011

Deposition parameters acting on nucleation and growth local conditions have been optimized in a bell jar microwave plasma reactor to obtain polycrystalline diamond thin films compatible with X-ray membrane requests. The microstructure and the chemical quality of the films were estimated by SEM and Raman spectroscopy respectively, the roughness was evaluated by AFM experiments and the residual stress was deduced from the substrate deflection method. Membranes were obtained by removing the silicon substrate on 15 mm diameter circular windows. The optical transparency depending on deposition conditions was optimized up to 65% at 630 nm for 1 μm thickness. A high resolution additive mask process, based on well taut membranes and low stress electroplated gold absorber, was carried out. Micrometric and submicrometric mask patterns were generated in photoresists both by electron beam lithography with a nanopattern generator and by X-ray lithography using the synchrotron radiation facility implemented at LURE-Orsay. Despite the diamond films roughness of the order of 30 nm, well defined dots and lines as narrow as 100–200 nm could be obtained.
Materials For Laser-Plasma X-Ray Source Targets Applicable To Lithography
Authors: Chaker M. , Pelletier J.F. , Kieffer J.C.
Published: March 2011

In recent years, several X-ray lithography experiments involving laser plasma sources have been reported. The high X-ray conversion efficiency (η – 10%) in the keV range observed in various laboratories, using high laser intensities (I > 5 × 1012 W cm−2), has already made these sources an attractive alternative to the electron storage rings for X-ray lithography in proximity printing (XRL). In addition, X-rayproduction in the region around 130 Å has also been investigated at intensities of about 1011 W cm−2 for applications to X-ray Projection Lithography (XRPL). Conversion efficiency up to 1% into a 3 Å bandwidth has been demonstrated. In principle, a large variety of X-ray spectra can be obtained from a laser plasma source depending on the laser-target parameters. However, high conversion efficiencies, in a given spectral range, can only be achieved under specific plasma conditions (target atomic number, plasma temperature, plasma volume and spatio-temporal expansion...). This leads to some restrictions in possible target materials and irradiation conditions (laser wavelength, laser intensity, pulse duration). In this paper, we will discuss this physical aspect basing our analysis on both the theoretical and experimental studies of the X-ray spectra in different X-ray energy ranges and for various target atomic numbers. In addition, we will examine issues related to the laser plasma X-ray source design for both XRL and XRPL applications.
Properties Of SiC Film As X-Ray Mask Membrane
Authors: Yamaguchi Yoh-Ichi , Annaka Norimichi , Shoki Tsutomu , Amemiya Isao , Nagasawa Hiroyuki , Kosuga Hiroyuki , Nagarekawa Osamu
Published: March 2011

Many properties of LPCVD SiC film as X-ray mask membrane have been investigated in detail. The film has an atomic ratio of 1.0 and negligible impurities, and was found to be damage-free to SR X-rays up to 500 KJ/cm2. An integrated transparency of 1.05 μm thick SiC membrane for SR X-rays was measured to be 76%. The interference peak at 633 nm of optical spectrum has given the membrane of around 1.0 μm in thickness the transmittance peak of 70% and increased to more than 80% after an AR coating or planarizations by polishing and etching-back. The attainable transmittance was found to be limited to about 84%, theoretically and experimentally, due to the absorption of the membrane. The peak transmittance of 87% is obtainable by the AR coating on the polished SiC membrane. The internal stress was found to be independent of thicknesses above 0.6 μm and the measured Young's modulus is 4.5×1011 Pa irrespective of the thickness and stress. Some extremely polished (0.1 nm Ra) and all the etched-back membranes studied withstood breakage at the pressure as high as the as-deposited ones. The stress uniformity in 30 mm square of the membrane was found to be ± 10 % by measuring five local stresses with a bulge method.
Materials Issues In X-Ray Mask Repair by Focused Ion Beams
Authors: Melngailis John
Published: March 2011

In x-ray mask repair high Z absorber features, such as gold or tungsten, must be removed or added. The main challenges are the small lateral dimensions (0.25 μm and below) and the thickness of the absorbers (˜ 0.5 μm) The focused ion beam appears to be the best tool developed to meet this challenge. Unwanted features are removed by ion milling while missing absorber is reconstructed using ion induced deposition from a locally piped-in precursor gas. The high aspect ratio of the features complicates both of these processes. Milling away 0.5 μm thick absorber can lead to redeposition of the sputtered material on neighboring features. The crystal grains of the absorber mill at different rates depending on orientation which results in nonuniform features. A possible alternative which only works with W absorber is to use ion assisted etching. In ion induced deposition a precursor gas such as dimethylgold hexafluoro acetylacetonate is provided by a capillary tube aimed at the region scanned by the ion beam. The incident Ga+ ions, usually at energies in the 25–100 keV range, dissociate the adsorbed precursor molecules leaving a deposit of gold mixed with carbon. The carbon content can approach 50 atomic % resulting in an x-ray attenuation which is about one half of that of pure gold. A number of unexplored materials science issues are associated with mask repair including: the reduction of the carbon content, redeposition both from milling and from induced deposition, milling as a function of crystal orientation and energy, and deposition of high aspect features. The technology is well enough developed so that mask repair of 0.25 μm features can be considered. However, a better understanding of the materials science aspects of x-ray mask repair will help to advance the state-of-the-art.
Electrodeposited Gold: Real Time Stress And Structural Change At Room Temperature.
Authors: Acosta R. E. , Babich I. , Blauner P. , Wagner A.
Published: March 2011

In this work the stress and grain structure of electrodeposited gold films was determined as a function of time from deposition, with measurements being conducted in time intervals of minutes to days after deposition.

A test structure that allows accurate and unambiguous measurement of out of plane distortion (OPD) was developed. Using this structure the time evolution of the stress of the films was followed using an interferometric microscope. Scanning ion microscopy was used to determine the time evolution of the grain structure of the samples. This technique, based on focused ion beam imaging, allows determination of grain structure of thin films without special sample preparation or restrictions in film thickness.

The sign, magnitude, and stability of the stress at room temperature was found to be a function of the rate of deposition and the concentration of additive in the electrodeposition solution.

For some of the films studied, grain growth from the hundreds of Angstroms to tens of microns was found to occur in a matter of minutes at room temperature.
Materials Issues In X-Ray Lithography
Authors: Dobisz E.A. , Peckerar M. C. , Chut W. , Rheet K. , Shirey L. S. , Marrian C. R. K. , Salvino R. E. , Foster K. , Kosokowski J.
Published: March 2011

In this paper, an outline of materials-related activities in the national X-Ray Lithography Program is given. The program is directed towards the development of sub-quarter micron design-rule x-ray lithography together with the ancillary technologies required to fabricate defect-free x-ray masks. Work done at the Naval Research Laboratory is highlighted and used for examples. Most materials related work occurs in conjunction in the x-ray mask fabrication pro. cess. Topics discussed include electron beam-matter interaction in the mask patterning process, membane fabrication, stress control in thin membranes, reactive-ion etching of absorber-layers, mask inspection and repair.
The Design And Performance Characteristics Of X-Ray Sensitive Resists
Authors: Novembre Anthony E.
Published: March 2011

The drive towards < 0.5 μm design rules in silicon device fabrication has led to the emergence of evaluating lithographic technologies based on the use of x-rays as the exposure source. X-rays (centered @ λ = 1.4 nm) emanating from a pulsed laser point source based system has been used for resist design purposes. Concurrent with the development of this exposure source has been the search for a resist which will provide high sensitivity ( ≤ 20 mJ/cm2) and resolution. The vast majority of resists in which the x-ray induced chemistry is amplified are viewed as the most promising class of materials to meet the high sensitivity requirement. Central to these so-called chemically amplified resists is the exposure induced generation of an acid catalyst. The acid during the subsequent post exposure bake (PEB) processing step removes a functionality in the resist resulting in film loss in the exposed regions and dissolution of those areas in the aqueous base developer. To date, the majority of such resists are multi-component which adds complexity to processing of these materials. Chemically amplified resists based on poly 4- t-butoxycarbonyloxystyrene and sulfur dioxide are shown to minimize this complexityThe novel insitu generation of the catalytic acidic species is presented, and the performance of these resists is improved through the use of model compounds based on arylmethyl sulfones.
Characterization of a Silicon Nitride Mask Membrane Process
Authors: Wells G.M. , Reilly M. , Nachman R. , Cerrina F. , Khakani M. A. El , Chaker M.
Published: March 2011

A silicon nitride membrane growth process has been characterized. The films were grown by LPCVD on 100 mm diameter silicon substrates using ammonia and dichlorosilane as reactant gases. The films were grown using a range of gas ratios at three different temperatures. The film composition was determined by elastic recoil detection. The silicon-nitrogen absorption bands were characterized by FTIR spectroscopy. The photon transmission of the films was measured in the visible region from 350 – 850 nm, and in the x-ray region for photon energies from 1000 to 3000 eV. The film stresses were determined using the wafer bow technique. An increase in the silicon content of the films was observed for increased dichlorosilane gas flow and for increasing growth temperatures. The increased silicon content of the films is correlated to a decrease in the tensile stress and a decrease in the optical transmission of the films.
Evidence of Distortion in the Oxygen Environment around Praseodymium in Y1−xPrxBa2Cu3O7 from Praseodymium K-Edge XAFS
Authors: Booth Corwin H. , Bridges Frank , Cervantes Phillip , Boyce Jim , Claeson Tord
Published: March 2011

In constrast to other rare earths, replacement of Y with Pr in the high Tc superconductor YBa2Cu3O7 has a pronounced effect on Tc, with Tc going to zero at ≈ 55% Pr. We present Pr XAFS K-edge data for various concentrations of Pr in Y1−xPrxBa2Cu3O7. The Pr K-edge data show that the amplitude of the first Pr-O peak is greatly reduced when compared to the first Y-O peak in pure YBa2Cu3O7. In constrast, for the Y K-edge data in these alloys, there is little if any change in the oxygen environment, while the Cu K-edge data show at most a 10% reduction in the first Cu-0 peak. Fits to the Pr data suggest either that oxygen atoms in the CuO2 planes are missing or that some oxygen atoms about the Pr become highly disordered. Either result could help explain the reduction of Tc with increasing concentration of Pr.
EXAFS Analysis of Dilute Magnetic Semiconductor Thin Films Synthesized by the Ion Beam Technique
Authors: Yu Kin Man , Ager J. W. , Bourret E. , Derhacobian N. , Giauque R. , Jaklevic J. M. , Becla P. , Rossington C. , Walukiewicz W. , Wesela M. , Yao X.
Published: March 2011

We have synthesized dilute magnetic semiconductor (DMS) thin films of CdMnTe and ZnMnSe using the ion beam technique. High doses of Mn ions (∼2–5×1016/cm 2) were implanted into single crystal CdTe and into ZnSe epilayers on GaAs, forming subsurface layers of Cdl.xMnxTe and Znl-xMnxSe alloys, respectively, with x∼0.15–0.22. Fluorescence extended x-ray absorption fine structure (EXAFS) measurements on these materials reveal that the Mn atoms in the CdMnTe and ZnMnSe layers, both as-implanted and annealed, have local environments similar to their corresponding bulk-grown DMS alloys. While the anion-cation distances (Ra-c) in the annealed samples are equivalent to those in the corresponding bulk-grown DMS, the Ra-c in the asimplanted samples are slightly larger (∼0.01Å) than those in the bulk-grown DMS. This is most likely due to the implantation damage in the as-implanted materials. Our results on the Ra-c of the ion beam synthesized layers deviate significantly from Vegard's law, but are consistent with the bimodal distribution model. The EXAFS results are corroborated with results from ion beam analysis and Raman spectroscopy.
X-Ray Topography
Authors: Dudley Michael
Published: March 2011

A review of the technique of White Beam Synchrotron X-ray Topography is presented along with some examples of its applications in materials science. Among the topics covered are: the characterization of growth defects in KTiOPO4, ZnTe, and SiC single crystals; studies of phase transitions in perovskite-like crystals; and studies of rapid thermal processing damage in semiconductors. Methodologies for analyzing dislocations, twins (rotational, mirror and inversion twins), precipitates and other crystallographic defects, will be reviewed.
Characterization of Defect Structures in SiC Single Crystals Using Synchrotron X-Ray Topography
Authors: Wang S. , Dudley M. , Carter C. , Asbury D. , Fazit C.
Published: March 2011

Synchrotron white beam X-ray topography has been used to characterize defect structures in 6H-SiC wafers grown on (0001) seeds. Two major types of defects are observed: super screw dislocations approximately perpendicular to the basal plane and dislocation networks lying in the basal plane. The super screw dislocations, which have open cores, are growth dislocations. These dislocations act as sources and/or sinks for the glide dislocation networks. Detailed analysis and discussion of dislocation generation phenomena and Burgers vectors will be presented.
Characterization of Cleaved GaAs(110) with a Scanning Photoemission Microscope Capable of Submicron Resolution
Authors: Ray-Chaudhuri A. K. , Ng W. , Liang S. , Singh S. , Solak H. , Cerrina F.
Published: March 2011

We have utilized a scanning photoemission spectromicroscope with sub-micron spatial resolution to observe microscopic Fermi level pinning on the cleaved GaAs(110) surface. We present micrographs which identify pinning that is highly localized to the vicinity of a single linear cleavage step. This extends previous work utilizing scanning Kelvin probe and imaging photoelectron microscopy conducted at lower spatial resolution. A sub-monolayer coverage of In uniformly pins the surface, thus allowing us to observe only the image contrast mechanism resulting from topography. From this one can determine the spatial extent of defects near a cleavage step. Initial observations indicate that Fermi level pinning can extend from a cleavage step over the range of 2 μm. This indicates the additional presence of defects at the adjacent surfaces of the step.
Hard X-ray Sputtered-Sliced Phase Zone Plates
Authors: Bionta Richard M. , Skulina Kenneth M.
Published: March 2011

Al/Cu sputtered-sliced phase zone plates, designed to operate with a focal length of 0.18 m and 1.12 m at 8.05 keV, were tested at the Stanford Synchrotron Radiation Laboratory. The results of lens characterization and the implementation of a microscope are reported.
Real Time Structural Electrochemistry of Platinum Clusters using Dispersive XAFS
Authors: Allen P. G. , Conradson S. D. , Wilson M. S. , Gottesfeld S. , Raistrick I. D.
Published: March 2011

Chemical reference tables state that the standard potential for the reaction of Pt with water, Pt + 2H2O → Pt(OH)2+ 2H++ 2e−, is 0.98 V, and electrochemical studies propose that this reaction may occur at potentials as low as 0.8 V [1–5]. Using dispersive x-ray absorption finestructure (XAFS) spectroscopy [6], we have directly probed the structural evolution of a Pt catalyst operating in-situ in a polymer electrolyte [7] fuel cell during cyclic voltammetry. The changes in the number of Pt and O nearest-neighbors and the Pt charge demonstrate a close correspondence with features in the voltammogram. Because dispersive XAFS is very sensitive to detecting structural changes, we have been able to detect the presence of chemisorbed oxygen at potentials of 0.6–0.9 V in the anodic sweep. Since double-layer charging is regarded as the only process in this region for bulk Pt [3–5], these results may reflect a limitation of previous (indirect) studies on Pt electrochemistry, or they may indicate that these clusters are different from their bulk metal counterparts. Exploiting the timeresolving capability of dispersive XAFS, we also monitored changes in the Pt charge and the number of O and Pt nearest-neighbors during the electrochemical oxidation and reduction of the Pt clusters in real-time. The results are inconsistent with those expected from the placeexchange mechanism [8–11] for the formation of the surface oxide on bulk Pt electrodes in aqueous solution;

Our current model for understanding these behaviors is that, relative to bulk Pt, unusual types of surface sites play a major role in determining the reactivity of these clusters.
An overview of Analytical Electron Microscopy
Authors: Williams D. B.
Published: March 2011

Analytical electron microscopy techniques comprising imaging, chemical analysis and microdiffraction are described together with details of the instrumentation required. Using the analytical electron microscope (AEM), the materials scientist can gain combined chemical and crystallographic information with a spatial resolution and sensitivity not available in other imaging instruments. Examples of the application of the AEM to determine solute distribution and crystal structure data are given.
Effects of Microstructure and Chemical Composition on Ebic Contrast in Hem Solar Cell Silicon
Authors: Sullivan T.D.
Published: March 2011

EBIC images of an HEM solar cell display extensive spatial innomogenieties in the production of short-circuit current. TEM imaging reveals a variety of morphologies having dimensions on the order of 10 Um embedded in the material.Correlation of a region with high current collection to one or these distinct morphological regions suggests that segregation or B is responsible for the EBIC contrast.
Structure of Thermally-Induced Microdefects in Czochralski Silicon
Authors: Ponce F. A. , Hahn S.
Published: March 2011

The process of oxygen precipitation in Czochralski silicon materials has been studied using high resolution transmission electron microscopy. The resulting structure depends strongly on the thermal history of the material. The initial stages of precipitation involve the formation of clusters exhibiting strain fields which are coherent and isotropic at intermediate temperatures (∼7000°C). Incoherent defects are formed when the interstitial oxygen precipitates into substitutional sites in the silicon lattice. For long-time anneals, the quasi-equilibrium defect structure ranges from needle-like coesite (450–600°C), silica platelets (600–1000°C) to polyhedral silica precipitates (900–1200°C).
Computer Interfaced Electron Microscope
Authors: Kokubo Y. , Moriguchi S. , Hosoi J. , Watanabe E. , Nash J.
Published: March 2011

Some applications of the computer for the electron microscope, in three major areas - 1) control of the microscope,2) image processing, and 3) structure Analysis - are discussed in the present paper.
Stem Microanalysis of Hazed Polycrystalline Silicon Layers
Authors: Carpenter G.J.C. , Houghton D.C.
Published: March 2011

The LPCVD of polysilicon on oxidized silicon wafers sometimes results in defective material having a “hazed” appearance. Examination of this material by SEM has revealed surface nodules which correlate on a one-to-one basis with anomalously large silicon grains, observed by transmission microscopy. Darkfield microscopy has shown that this abnormal grain growth initiated during deposition. X-ray EDS analysis of isolated poly-Si nodules revealed the presence of metallic impurities.
Misfit Dislocations in the Interface between the Metallic and Insulating Phases in Cr Doped V203
Authors: Otsuka Nobuo , Sato Hiroshi
Published: March 2011

The formation of misfit dislocations in the interface between the metallic and insulating phases which occur in 1.2% Cr doped V203 near room temperature was confirmed by TEM. Orientations of Burgers vectors of misfit dislocations were determined by the weak beam technique. The Burger vectors were parallel to principal axes in the basal plane (<100>) and inclined somewhat to interfaces. The Burgers vectors of misfit dislocations are, however, close enough to the direction of the maximum misfit in the interface. Only one or two misfit dislocations appear in an interface regardless of the thickness of specimens, and these were always located near the surface.
Applications of High Resolution Electron Microscopy in Ceramics Research
Authors: Van Tendeloo G.
Published: March 2011

High resolution microscopy of ceramics has its specific problems due to the difficulties in preparing thin foils. Most of these Problems however can be overcome and recent years a lot of effort has been concentrated on electron microscopy of ceramics because of their high technological importance. Some results on important ceramics such as SiC, Mg-Si-O, ZrO2 -ZrN and Si-Al-O-N obtained by high resolution microscopy will be briefly discussed here.
Calcium Site Occupancy in BaTiO3
Authors: Chan H. M. , Harmer M. P. , Lal M. , Smyth D. M.
Published: March 2011

Measurements of the equilibrium electrical conductivity of Ca-doped BaTiO3indicate a highly acceptor-doped behavior when y > 1 in the general formula (Ba1−xCaxO)yTiO2. It has been suggested that when there is an excess of alkaline earth oxides, some Ca++occupies Ti-sites, where it acts as a doubly charged acceptor, CaTi''. This possibility has been checked with a recently developed technique for determining the crystallographic site occupancy of impurity atoms. Known as ALCHEMI (Atom Location Using Channeling-Enhanced Microanalysis), the technique relies on the dependence of the characteristic X-ray emission on the incident electron beam direction. A significant channeling effect was observed for slightly positive and negative excitations of the [100] reflection. The results indicate that for the composition (Ba0,85Ca0.15O)1.02TiO2.00, a substantial fraction of the total calcium (> 20%) occupies Ti sites.
Determination of the Specific Site Occupation of Rare Earth Additions in Y17Sm06,Lu07Fe5O12Thin Films by the Orientation Dependence of Characteristic x-Ray Emissions
Authors: Krishnan Kannan M. , Rez Peter , Mishra Raja , Thomas Gareth
Published: March 2011

The orientation dependence of characteristic x-ray emissions have been used to determine specific site occupations of Rare Earth additions in epitaxially grown films of Y1.7Sm0.6Lu0.7Fe12.A.theoretical formulation based on the assumption of highly localiszed inner shell excitations was used not only to oredict specific site sensitive orientations, but also to refine experimentally observed data employing a constrained least squares analysis to give probabilities for the occupation of the RE additions in the different crystallographic sites. Thus, it has been shown that in this compound the preference for the RE additions is a predominantly octahedral occupation with a probability ≳95%. Some of theassumptions and limitations of the technique have also been discussed.
Tem/Ebic Investigations of Structural Defects in Polycrystalline Solar Cells
Authors: Ast D.G. , Cunningham B. , Gleichmann R.
Published: March 2011

Most solar silicon is grown in the form of cast ingots, e.g. HEM, Silso and UCP or in the form of thin continous ribbons, e.g. FFG, RTR and Web. HEM and EFG will be considered as representative example of each catagory.
Progress Toward Viable Epitaxial Oxide Ferroelectric Waveguide Heterostructures on Gaas
Authors: Fork D. K. , Kingston J. J. , Anderson G. B. , Tarsa E. J. , Speck J. S.
Published: March 2011

Discoveries within the last two years have created possibilities for the fabrication of epitaxial oxide heterostructures on GaAs substrates. In particular, magnesium oxide, MgO, may have broad applications, including its use as a cladding layer in optical waveguides. This report expands upon earlier work by revealing additional epitaxial structures involving lithium niobate which have been grown. There are now five known variants of Z-lithium niobate on GaAs: direct Z-cut growth on GaAs (111)A or B, Z-cut growth on MgO (111)/GaAs (111)A or B, and Z-cut growth on MgO (111)/GaAs (001). Broad in-plane misalignment (about 15°) characterizes the latter structure, whereas the former posses a textural width of 3° to 5° in the plane. All structures contain internal boundaries resulting from 180° rotations about the Zaxis. A critical issue for any ferroelectric heterostructure is its integrity in the presence of thermally induced tensile strain. Approaches to the mitigation of thin fim fracture are discussed and a novel approach to strain relief via ridge waveguide fabrication is reported.
Chemical Vapor Deposition of Epmtaxial BaTiO3 Films for Frequency Doubling Devices
Authors: Van Buskirk Peter C. , Stauf Gregory T. , Gardiner Robin , Kirlin Peter S. , Bihari B. , Kumar J.
Published: March 2011

Ferroelectric materials such as BaTiO3 are notable for their nonlinear optical and electrical properties. Optical frequency doubling in thin films integrated with compact semiconductor laser pumped solid state lasers is an attractive candidate for high efficiency generation of blue light. Chemical vapor deposition (CVD) using a single liquid source has been used to grow BaTiO3 films on MgO. X-ray diffraction in the pole figure configuration indicates the films to be epitaxial, and rocking curves had FWHM ≈ 0.7°. An optical scatterometer (λ = 633 nm.) has been used to identify deposition conditions that result in the lowest scatter losses. This paper describes these results as well as waveguide designs to enhance the second harmonic generation efficiency in epitaxial BaTiO3 films on MgO.
Reactive ion Etching of PbZrxTi1−xO3 and Ruo2 Tein Films
Authors: Vijay Dilip P. , Desu Seshu B. , Pan Wei
Published: March 2011

In this work, we have identified a suitable etch gas (CCI2,F2 ) for Reactive Ion Etching (RIE) of PZT thin films on RuO2 electrodes. The etch rate and anisotropy have been studied as a function of etching conditions. The effect of gas pressure, RF power and O2 concentration on the etch rate have been determined. It was found that ion bombardment effects are primarily responsible for the etching of both PZT and RuO2 thin films. Etch rates of the order of 20-30 nm/min were obtained for PZT thin films under low gas pressure and high RF power conditions. The etch residues and the relative etch rates of the components of the PZT solid solution were determined using XPS. The results show that the etching of PbO is the limiting factor in the etch process. For RuO2 thin films, etch rates of the order of 8-10 nm/min were obtained when O2 was added to the etch gas.
Epitaxial Ferroelectric Heterostructures of Isotropic Metallc Oxide (SrRuO3) and Pb(Zr0.52Ti0.48)O3
Authors: Eom C. B. , Van Dover R.B. , Phillips Julia M. , Fleming R.M. , Cava R.J. , Marshall J.H. , Werder D.J. , Chen C.H. , Fork D.K
Published: March 2011

We have fabricated epitaxial ferroelectric heterostructures of isotropic metallic oxide (SrRuO3) and ferroelectric thin films [SrRuO3/Pb(Zr0.52Ti0.48)O3 /SrRuO3] on (100) SrTiO3 and YSZ buffer layered Si substrates by 90° off-axis sputtering. These heterostructures have high crystalline quality and coherent interfaces as revealed by X-ray diffraction, Rutherford backscattering spectroscopy and cross-sectional transmission electron microscopy. The ferroelectric layers exhibit superior fatigue characteristics over 1010 cycles with large remnant polarization.
Impact of Backend Processing on Integrated Ferroelectric Capacitor Characteristics
Authors: Maniar P.D. , Moazzami R. , Jones R.E. , Campbell A.C. , Mogab C.J.
Published: March 2011

Integration of a ferroelectric capacitor module in a standard CMOS process subjects the ferroelectric to various ambients during backend processing, some of which can render the ferroelectric essentially non-operational for NVRAM applications. Post-crystallization processing of sol-gel deposited integrated ferroelectric PZT capacitors in the presence of hydrogen-containing, reducing ambients is observed to degrade the nonvolatile polarization. Low-pressure hydrogen anneals at temperatures as low as 200°C substantially degrade the nonvolatile polarization while the DRAM polarization remains roughly constant. Leakage current drops by one order of magnitude and fatigue is accelerated. A ferroelectric capacitor module can be integrated with minimal degradation with careful modifications in the backend processing.
Textured Pb(Zr0.54Ti0.46)O3 Thin Films with YBa2Cu3O7-δ and Yttria-Stabilized Zirconia Buffer Layers on (001)Si
Authors: Zheleva Tsvetanka , Tiwari P. , Narayan J.
Published: March 2011

Characteristics of textured Pb(Zr0.54Ti0.46)O3 (PZT) thin films on (001)Si with YBa2Cu3O7-δ (YBCO) and yttria-stabilized zirconia (YSZ) buffer layers have been studied using X-ray diffraction and high resolution electron microscopy techniques. Excimer KrF laser has been used for deposition of PZT, YBCO and YSZ thin films. The YBCO layer was utilized to provide a seed for PZT growth, while YSZ layer acted as a seed and a buffer layer for the growth of YBCO on (001)Si. High-resolution transmission electron microscopy (HRTEM) and X-ray diffraction were used to determine the texture and the nature of defects, interfaces and grain boundaries. Predominant orientation relationships were found to be [001]PZT//[001]YBCO; [001]YBCO//[001]YSZ; and [001]YSZ//[001]Si.
Organometallic Chemical Vapor Deposition of Lead Zirconate-Titanate Thin Films
Authors: Keuser M. De , Veldhoven P.J. Van , Dorman G.J.M.
Published: March 2011

In this paper the growth of PbZrxTi1-xO3 on 10 cm platinized silicon wafers using the precursors cursors tetra-ethyl-lead, titanium-tetra-isopropoxide, or titanium-tetra-tertiarybutoxide and zirconium-tetra-tertiarybutoxide will be discussed in some detail. The composition of the films as a function of growth parameters will be treated and the accompanying change in the ferroelectric properties will be discussed. For device manufacturing, the PbZrxTi1-xO3 films are subjected to a number of processing steps. Some results for partially processed wafers will be presented. Also, preliminary results of depositions on 15 cm wafers will be given.
Ferroelectric Properties of a-Axis Textured BaTiO3 Thin Films
Authors: Lu H. A. , Wills L. A. , Wessels B. W. , Zhan X. , Helfrich J. A. , Ketuerson J. B.
Published: March 2011

Ferroelectric and dielectric properties were measured for BaTiO3 thin films prepared by metalorganic chemical vapor deposition which were highly a-axis textured. No ferroelectric hysteresis was observed from the as-deposited BaTiO3 films on Pt coated MgO. Upon applying an electric field exceeding a threshold electric field, Et, ∼ 50 - 100 kV/cm, a ferroelectric hysteresis was observed. A spontaneous polarization Ps ≥ 15 μC/cm2 was measured for the textured films.
Preparation and Characterization of Epitaxial KNBO3 Thin Films by a Sol-Gel Method
Authors: Endo Hidehiro , Cima M. J.
Published: March 2011

Epitaxial formation of KNbO3 films on several substrates was examined. The films were prepared by a sol-gel process using potassium ethoxide and niobium pentaethoxide. Hetero-epitaxial KNbO3 films with (100) orientation were successfully obtained both on MgO (100) and SrTiO3 (100) substrates by heat treatments above 700°C, while polycrystalline KNbO3 were formed on Si (111) substrates. Higher temperatures and extended soaking time promoted the grain growth of KNbO3 and KNbO3 films with improved surface morphologies (smoother surfaces) could be obtained by controlling heat treatment parameters.
Microstructural Changes Due to Process Conditions in Sol-Gel Derived KNbO3 Thin Films
Authors: Derderian G.J. , Barrie J.D. , Aitchison K.A. , Adams P.M. , Mecartney M.L.
Published: March 2011

KNbO3 thin films have been deposited from K(OMe)/Nb(OMe)5 sols onto (100) MgO substrates. Microstructural changes were observed relative to stoichiometry, aging, and the hydrolysis temperature. The production of single phase, oriented films has been demonstrated, and was found to be strongly dependent on process conditions. The films were characterized by XRD, TEM, SEM, EDS, and Raman spectroscopy.