bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electron Microscopy at Atomic Resolution
Authors: Gronsky R. 
Published: March 2011

ABSTRACTThe direct imaging of atomic structure in solids has become increasingly easier to accomplish with modern transmission electron microscopes, many of which have an information retrieval limit near 0.2nm point resolution. Achieving better resolution, particularly with any useful range of specimen tilting, requires a major design effort. This presentation describes the new Atomic Resolution Microscope (ARM), recently put into operation at the Lawrence Berkeley Laboratory. Capable of 0.18nm or better “interpretable” resolution over a voltage range of 400 kV to 1000kV with ± 40° biaxial specimen tilting, the ARM features a number of new electron-optical and microprocessor-control designs. These will be highlighted, and its atomic resolution performance demonstrated for a selection of inorganic crystals.
Crystallinity, Morphology, and Conductivity of Boron-Doped Microcrystalline Silicon
Authors: Rajeswaran G. , Tafto J. , Sabatini R. L. , Vanier P. E. 
Published: March 2011

ABSTRACTBoron-doped microcrystalline (μc) silicon films produced by rf glow discharge from dilute (1%) mixtures of SiH4 in H2 show a critical dependence of conductivity on deposition conditions. The dark conductivity was related to the microscopic features using electron microscopy. The μc−Si:H films contain clusters of crystallites embedded in an amorphous matrix. The size of the crystalline clusters is typically 0.2 μm in diameter, and the size of the individual crystallites is about 2.5 nm. Electron micrographs of samples prepared at substrate temperatures Ts=135°C, 150°C, 165°C, and 180°C show that the number of crystalline clusters increases with Tsup to 165°C. At Ts=180°C, the crystallites completely disappear. When the concentration of SiH4 in H2 is decreased to 0.25%, the microstructure shows a high density of crystallites with no apparent clustering.
Reflection Electron Microscopy and Diffraction from Crystal Surfaces
Authors: Cowley J.M. 
Published: March 2011

ABSTRACTThe recent revival of techniques for the imaging of crystal surfaces, using electrons forward-scattered in the RHEED mode and employing modern electron microscopes, has lead to the introduction of valuable new methods for the study of surface structure. Either fixed beam or scanning transmission electron microscopy (STEM) instruments may be used and in each case a lateral resolution of 10Å or better is possible. Simple theoretical treatments suggest that the contrast from surface steps may be attributed to a combination of phase-contrast, diffraction contrast and geometric effects. With a STEM instrument the image information can be combined with information on the local composition and crystal structure by use of microanalysis and microdiffraction techniques. Examples of applications include studies of the surface structure of metals, semiconductors and oxides, and the surface reactions.
Interpretation of the Atomic Surface Structure of Ag2O on (111) Au thin films
Authors: Krakow William 
Published: March 2011

ABSTRACTA high resolution electron microscope investigation of the residual oxidized silver of a few monolayers thickness on the surface of (111) Au films has shown that a reconstructed (2×1) surface structure occurs for (110) oriented Ag2O and can be observed at atomic resolution levels. Image enhancement via a digital frame store processor has revealed improved images which have then been compared to computer simulated diffraction patterns and images of the Ag2O surface. Several iterations of surface structure models and image simulations reveal that the (2×1) reconstruction is consistent with a missing row model. The atomic arrangements of these rows often undergo a translation along the direction of the row to produce cusp like image features. It has also been possible to observe the effect of contraction of the underlying layer which can produce diagonal contrast lines in the images. These features often vary rapidly over lateral distances of a few tens of angstroms and give an indication of the surface topography and the degree ordering of the surface.
Dislocations, Steps and Interphase Boundary Migration
Authors: Smith D.A. 
Published: March 2011

ABSTRACTInterface migration is the fundamental process in numerous phase transformations. For those which are thermally activated the basic event is addition of atoms to a defect in an interface. Interfacial defects can have a range of topographic and elastic characteristics which complicates investigations by transmission electron microscopy, it is difficult to make quantitative in-situstudies of interface migration because of problems of resolution and control of driving forces in specimens where surface effects dominate.
High Resolution Study of the Relationship Between Misfit Accommodation and Growth of CU2-xS in Cds
Authors: Sands T. , Washburn J. , Gronsky R. 
Published: March 2011

ABSTRACTThe growth of CU2-xS in the (0001) basal face of single crystal cadmium sulfide has been studied with high resolution transmission electron microscopy (HRTEM) and diffraction. Cross-sectional Cu2-xS/CdS specimens and plan-view Cu2-xS separated films were prepared from heterojunctions formed by the aqueous conversion of CdS to topotaxial Cu2-xS. Low chalcocite films were found to form in two principal stages; 1) coalescence of low chalcocite islands and 2) an accelerated reaction localized at pores in the Cu2-xS film. Several possible misfit accommodation mechanisms involving twinning, cracking, and a second copper sulfide phase were identified.
Fault Structures in CVD Silicon Nitride
Authors: Shaw T.M. , Steeds J.W. , Clarke D.R. 
Published: March 2011

ABSTRACTFault structures occurring in crystalline CVD silicon nitride deposits have been examined using transmission electron microscopy. A variety of mixed rotation and displacement faults are observed. The faults have extensive basal plane facets but also extend onto other planes within the grains. Possible structures for the faults are discussed with reference fo the structures of the a and P silicon nitride polymorphs.
Image Processing for Electron Microscope Investigations of Materials
Authors: Krakow William 
Published: March 2011

ABSTRACTA time shared television digital image processing system has been developed for on-line electron microscopy and uses a large mainframe computer. The main component of the system is a digital television frame store which has many standard features for digital analysis such as: digitization, zoom and pan, arithmetic and Boolean processors, alphanumeric generators and so on. Images can be acquired at atomic resolution from a TEM, analyzed in real time and hard copy slides made under full computer control. A full range of computer software has been developed or modified from existing software and is generally compatible with IBM Fortran compilers. Some of the areas where extensive menu driven software has been developed are: particle size and feature analysis, algebraic and geometric image manipulations, Fourier analysis, digitization and process control, image contrast correction, text processing, etc. A number of applications areas have been explored which include: the structure of Si/SiO2interfaces; nucleation of Au on rocksalt; the formation of hexatic structures from amorphous phases under shear, tension and compression; analysis of atomic surface structure and image motion and the analysis of field ion micrographs of amorphous structures. Several of these areas will be discussed in the context of image processing and materials characterization.
Dopant Site Location by Electron Channeling in Ion Implanted Silicon
Authors: Pennycook S. J. , Narayan J. , Holland O.W. 
Published: March 2011

ABSTRACTA simple ratio technique using the phenomenon of electron channeling can be used to measure the substitutional concentrations of dopants in semiconductors on a submicron scale.A comparison was made between electron and ion channeling measurements on Si-Sb alloy samples having a range of nonsubstitutional fractions of Sb.Good agreement was obtained but both measurements indicated considerably more nonsubstitutional dopant than could be accounted for by precipitates observed in electron micrographs. The discrepancy can be explained if the precipitates are coherent in the early stages of growth and have their planes located interstitially with respect to the Si planes. The sensitivity of the electron channeling measurements to the implantation profile was investigated and found to be small.The determination of local dopant profiles in the electron microscope is described.
Bottom Electrodes for High Dielectric Oxide Compounds: Effects on Crystallization of Lead Containing Ferroelectrics
Authors: Grill A. , Beach D. , Smart C. , Kane W. 
Published: March 2011

AbstractSeveral conductive structures, which appeared to be usable as base electrodes for integrated devices based on high dielectric materials, have been annealed for 30 minutes in oxygen at 650 °C. Similar structures coated with lead-based ferroelectrics deposited by the sol-gel method have been annealed for 1 min in oxygen at higher temperatures. The materials have been characterized by Rutherford backscattering (RBS) and scanning electron microscopy (SEM) and the crystallographic structure of the ferroelectrics films has been determined by X-ray diffractometry (XRD).Only RuO2/Ru has been found to be suitable as an electrode, at temperatures not exceeding 650 °C. It has also been found that the electrode materials can strongly affect the crystallization behavior of the sol-gel ferroelectric films and the formation of single-phase perovskite layers.
MOCVD Growth and Structure of PbTiO3 Thin Films
Authors: Gao Y. , Bai G. , Merkle K. L. , Chang H. L. M. , Lam D. J. 
Published: March 2011

AbstractPbTiO3 thin films grown on (001)MgO and (110)MgO by MOCVD have been characterized by x-ray diffraction and transmission electron microscopy. The PbTiO3 films deposited on (001)MgO under the optimum conditions always show a bi-layer structure. The top layer of the films near the free surface is c-axis oriented with the orientation relationship (001)[100]PbTiO3∥(001)[100]MgO. The bottom layer of the films near the substrate is a-axis oriented with (100)[001]PbTiO3∥(001)[100]MgO. 90° domains were observed, but only in the caxis oriented layers. The thickness of the a-axis oriented layers near the substrate decreases with decreasing the cooling rate. PbTiO3 films deposited on (110) MgO, however, are single-layer, epitaxial films with (101)[001]PbTiO3∥(110)[001]MgO.
Metallorganic Cheamcal Vapor Deposition (Mocvd) of Titanium-Based Ferroelectric Thin Films
Authors: Hendricks Warren C. , Desu Seshu B. , Si Jie , Peng Chien H. 
Published: March 2011

AbstractUsing hot-walled metallorganic chemical vapor deposition (MOCVD), thin fihns of lead zirconate titanate (PZT), lead titanate (PbTiO3 or PT) and bismuth titanate (Bi4Ti3O12 or BiT) were successfully prepared. For each material, titanium ethoxide (Ti(C2H5O)4) was used as the precursor for the titanium source, while lead bis-tetramethylheptadione (Pb(thd)2), zirconium tetrakistetramethylheptadione (Zr(thd)4) and triphenyl bismuth (Bi(C6H5)3) were used as sources for lead, zirconium and bismuth, respectively. Dense, specular and highly transparent films were obtained for all three materials. Deposition conditions are given for each of the materials as well as the properties of the resulting films as determined by XRD, SEM and UV-VIS-NIR spectrophotometry. Ferroelectric properties are also given for the PZT and BiT films; for PZT (%Zr = 41; %Ti = 9) annealed at 600 °C, the spontaneous polarization, Ps, was 23 μC/cm2 and the coercive field, Ec, was 65 kV/cm; for BiT annealed at 550 °C, the spontaneous polarization, Ps, was 27 μC/cm2 and the coercive field, Ec, was 240 kV/cm.
Growth and Characterization of Ferroelectric Pb(Zr,Ti)OM3 Thin Films by Mocvd Using A 6 Inch Single Wafer Cvd System
Authors: Shimizu Masaru , Fujimoto Masashi , Katayama Takuma , Shiosaki Tadashi , Nakaya Kenichi , Fukagawa Mitsuru , Tanikawa Eiki 
Published: March 2011

AbstractFerroelectric Pb(Zr,Ti)O3(PZT) films with a perovskite phase were successfully grown by MOCVD using a 6 inch wafer CVD system. A two step growth process was proposed to obtain perovskite PZT films at high gas supplying ratios of [Zr]/([Zr]+[Ti]). The electrical properties of the PZT films obtained were measured. Large area growths of PZT films were carried out and the uniform films could be grown on the entire area of a 6 inch Si wafer. It was also found that the step coverage characteristic of the films grown by MOCVD was good.
Crystallization Behavior and Electrical Properties of Wet-Chemically Deposited Lead Zirconate Titanate Thin Films
Authors: Merklein S. , Sporn D. , SchÖnecker A. 
Published: March 2011

AbstractA wet chemical deposition process for smooth and crackfree films in the system Pb(Zr 1-x Tix)O3 (PZT) has been developed. Final film thicknesses, reached with one coating step, were in the region of 1 μm. Starting from lead acetate trihydrate, zirconium- and titanium-n-propoxide, high molarity (> 2M) coating sols have been prepared that could be handled in air and were stable for more than 170 days.Films with compositions near the morphotropic phase boundary (x=47) and various lead contents were deposited on Pt-coated Si-wafers and Al2O3-substrates by a spin-on method. Wet films could be pyrolyzed and densified with a fast heat treatment without cracking. The crystallization of films into the desired perovskite structure started at comparatively low temperatures (ca. 530 °C) and proceeded rapidly at temperatures above 650 °C. A slight molar excess of lead and a proper heating rate were found to produce films with the best electrical properties. The films on platinized A12O3 substrates showed device-worthy dielectric and ferroelectric properties with typical values for Pn, EC, and ε, of 24 μC/cm2, 4.5 KV/mm and 650, respectively.
Substrate Influenced Nucleation and Crystallization of LiNbO3 Thin Films Made by Sol-Gel
Authors: Joshi Vikram , Roy Debasis , Mecartney Martha L. 
Published: March 2011

AbstractLithium niobate films were deposited on amorphous carbon, silicate glass, (0001) sapphire, and (100) silicon by spin or dip coating double metal ethoxide sols. The crystallinity and microstructure of the deposited films were examined by XRD and TEM. Crystallization behavior and resulting microstructure were strongly influenced by the type of substrate. The formation of crystalline LiNbO3 on amorphous carbon was detected at room temperature. Randomly oriented polycrystalline films were obtained on glass at 400°C. Choice of one mole of water per mole of ethoxide generated heteroepitaxial growth of LiNbO3 thin films on (0001) sapphire. Oriented but polycrystalline films were obtained on silicon. The electrical behavior of film on silicon was evaluated in metal-ferroelectric-semiconductor configuration. A dielectric constant of 35 and a dissipation factor of 0.004 was measured at 100 KHz.
Preparation and Characterization of Sol-Gel Derived Heteroepitaxial LiNbO3 and LiTaO3 Thin Films
Authors: Nashimoto Keiichi 
Published: March 2011

AbstractDense epitaxial LiNbO3 thin films without any misoriented plane on sapphire substrates were obtained with a sol-gel process utilizing 2-methoxyethanol based metal alkoxide precursors without pre-hydrolysis and rapid thermal annealing. Epitaxial LiNbO3 films annealed at 700°C were transparent and showed refractive indices close to bulk single crystal values. Epitaxial and transparent LiTaO3 films crystallized successfully on sapphire substrates with single orientations with the present process. X-ray rocking curve full widths at half maximum of epitaxial LiNbO3 and LiTaO3 films on sapphire (110) substrates and annealed at 700°C were less than 0.4 degree.
Microstructural Evolution of Pb(Zr,Ti)O3 Ceramics Using Electron Paramagnetic Resonance
Authors: Warren W. L. , Tuttle B. A. , Schwartz R. W. , Hammetter W. F. , Goodnow D. C. , Evans J. T. , Bullington J. A. 
Published: March 2011

AbstractUsing electron paramagnetic resonance (EPR) we have followed the microstructural evolution with temperature of lead zirconate titanate (PZT) ceramics from the amorphous to the perovskite phase. A number of paramagnetic point defects were identified (Carbon, Pb+3, and Ti+3) while traversing the evolution of these ceramics during various heat treatments both before and after optical illumination. Perhaps the most important finding is that the Pb+3 and Ti+3 centers can only be optically created in the perovskite materials, thereby, showing that they are not associated with the amorphous or the pyrochlore phases. It is also found that EPR signals attributed to carbon radicals are present in fairly high concentrations (4 × 1017/cm3) if the solution chemistry derived PZT materials are annealed in an oxygen deficient ambient (0.1% O2) at 650°C.
Low Temperature Preparation of BaTiO3 Films on Silicon
Authors: Pilleux M.E. , Fuenzalida V.M. 
Published: March 2011

AbstractInsulating BaTiO3 thin films were obtained on titanium coated silicon wafers using a novel low temperature technique. They were produced hydrothermally by introducing the substrate in a 0.25M Ba(OH)2 solution inside an autoclave and heating in the 200- 250°C range for 8 hours. This treatment delivered smooth pinhole-free films on the Ti with thicknesses ranging from 35nm (200°C) to 45nm (250°C), with grains in the 100- 300nm diameter range in all films. The films exhibited a dielectric constant up to 227, a breakdown field of 70MV/m, and a dc resistivity of 4.106Ωm.
Deposition of Dielectric Thin Films by Atomic Layer Epitaxy and Their Application for Electroluminescence Displays
Authors: Lee Dong Heon , Cho Yong Soo , Lee Jeon Kook , Jung Hyung Jin 
Published: March 2011

AbstractVarious dielectric thin films have been studied for electroluminescence display (ELD) application to improve dielectric constant and breakdown voltage. In this work, amorphous BaTiO3 thin films were deposited on indium tin oxide (ITO) - coated glass substrates by atomic layer epitaxy (ALE) using metalorganic precursors. Influences of deposition conditions on microstructure, interface characteristics and dielectric properties are investigated. It was possible to obtain dielectric films with good dielectric properties and textured, flat surface microstructure without defects due to the improvement of qualities of the grown films. These results were examined by XRD, SEM and AES analysis.
Prism-Film Coupling in Anisotropic Planar Waveguides of Epitaxial (101) Rutile Thin Films
Authors: Foster C. M. , Chan S.-K. , Chang H.L.M. , Chiarello R. P. , Lam D. J. 
Published: March 2011

AbstractWe report optical waveguiding in single-crystal, epitaxial (101) oriented rutile (TiO2) thin films grown on (1120) sapphire (α-Al2O3) substrates using the MOCVD technique. The propagation constants for asymmetric planar waveguides composed of an anisotropic dielectric media applicable to these films are derived. Modifications to the prism-film coupling theory for this anisotropic case are also discussed. By application of this model to (101) oriented rutile thin films, we directly obtain values of the ordinary and extraordinary refractive indexes, no and ne, of the rutile thin films as well as film thicknesses. We obtain typical values of the refractive indexes (no=2.5701±0.0005; ne=2.934±0.001) near to those for bulk rutile single crystals indicating the exceptional quality of these films.
Electrical Properties of Amorphous Thin Films of Ferroelectric Oxides Prepared by Sol-Gel Technique
Authors: Xu Yuhuan , Xu Ren , Cheng Chih-Hsing , Mackenzie John D. 
Published: March 2011

AbstractAmorphous thin films of ferroelectric oxides including lead zirconate titanate (PZT), barium titanate (BaTiO3) and lithium niobate (LiNbO3) on several kinds of substrates were prepared by a sol-gel technique. The heat-treatment temperatures for preparation of amorphous thin films were much lower than those for the corresponding crystalline ferroelectric thin films. Electrical properties of these amorphous thin films were measured and compared with those of corresponding crystalline films. These amorphous thin films exhibited ferroelectric-like behavior. A model of the microstructure of these films is proposed.
Pzt Thin Films on a Lead Titanate Interlayer Prepared by rf Magnetron Sputering
Authors: Ansari P. H. , Safari A. 
Published: March 2011

AbstractFerroelectric lead zirconate titanate (PZT) films with a composition near the morphotropic phase boundary have been deposited by if magnetron sputtering on a Si substrate coated with silicon oxide, titanium, and platinum (Si/SiO2/Ti/Pt). Substrate temperature and oxygen partial pressure were changed during deposition to prepare films with controlled stoichiometry and perovskite structure. The effects of lead titanate (PT) as a buffer layer were investigated. Thin films of PT/PZT have a dielectric constant of 800 with a dissipation factor of 0.04 at 1 kHz. The remnant polarization of 8μC/cm2 and the coercive field of 50 kV/cm were measured. The effect of processing on the formation of perovskite phase and the electrical properties will be discussed.
Effects of Process Parameters on the Ablated Flux Characteristics During Pulsed-Laser Ablation of Lead Zirconate Titanate (PZT)
Authors: Lichtenwalner D.J. , Auciello O. , Dat R. , Barnes R. , Schreiner A.F. , Hankins O.E. , Kingon A.I. 
Published: March 2011

AbstractWe have investigated the ablated flux characteristics of PbZrxTi1-xO3 as a function of deposition process parameters. The ablation-deposition rate, angular distribution, and type of ablated species axe all affected by the oxygen gas pressure. Visually, a change in the shape and color of the ablation plume are evident upon adding oxygen gas. The ablated flux distribution narrows as the oxygen pressure is increased, from a cos40θ distribution in a low gas pressure, up to a cos 260θ distribution at an oxygen pressure of 300 mTorr. This narrowing, or focusing, of the ablated plume also results in an increased deposition rate along the plume centerline for high laser power. However, at low laser power the deposition rate decreases as the pressure is increased, due to gas scattering effects. The energy of depositing species and the ratio of deposition flux to O2 flux will then be very different in each of these two regimes. The species in the plume have been examined using optical emission spectroscopy. We have found that mostly atomic species are present, but the ratio of ions to neutrals is very different for the Pb, Zr, and Ti atoms. Therefore, the application of electric fields near the substrate would affect the film composition to some degree.
The Application of Optical Interferometry to the Study of Field-Induced Effects in Bulk and thin Film Ferroelectrics
Authors: Lewis Keith L , Dexter Kathleen F 
Published: March 2011

AbstractA study is reported of field-induced effects in ferroelectric materials using optical interferometry. One of the techniques used is based on the use of a WYKO TOPO3 system and provides a three dimensional representation of field-induced displacement. The information provided is supplemented by optical transmission measurements on thin sections of material fabricated to allow interference fringing to be seen. Initial work has centred on the characterisation of ceramic PLZT material. Both transverse and longitudinal electrode configurations have been studied and have highlighted the magnitude of the effects possible and the importance of electrostrictive processes in determining the direction of deformation. These can result in anomalously high strain gradients over distances of the order of 50-100µm. This behaviour is compared with that found for preliminary samples of thin film ferroelectric materials.