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A specially constructed metallograph for use at elevated temperatures

Description: "A metallographic microscope was developed with provision for heating a specimen to 1800 F in protective atmospheres, that is, vacuum or gas. A special objective was constructed of reflecting elements with an unusually long working distance (7/16 in.) and a high numerical aperture (0.5). Changes in specimen microstructure were observed and recorded on 35-millimeter motion-picture film. The resulting pictures were projected as motion pictures and individual frames were cut and enlargements made for close observation" (p. 1).
Date: September 11, 1951
Creator: Jenkins, Joe E.; Buchele, Donald R. & Long, Roger A.
Partner: UNT Libraries Government Documents Department

Electronic contribution to friction on GaAs

Description: The electronic contribution to friction at semiconductor surfaces was investigated by using a Pt-coated tip with 50nm radius in an atomic force microscope sliding against an n-type GaAs(100) substrate. The GaAs surface was covered by an approximately 1 nm thick oxide layer. Charge accumulation or depletion was induced by the application of forward or reverse bias voltages. We observed a substantial increase in friction force in accumulation (forward bias) with respect to depletion (reverse bias). We propose a model based on the force exerted by the trapped charges that quantitatively explains the experimental observations of excess friction.
Date: April 15, 2008
Creator: Applied Science and Technology Graduate Group, UC Berkeley; Dept. of Materials Sciences and Engineering, UC Berkeley; Salmeron, Miquel; Qi, Yabing; Park, J.Y.; Hendriksen, B.L.M. et al.
Partner: UNT Libraries Government Documents Department

Thorough characterization of a EUV mask

Description: We reported that we were successful in our 45nm technology node device demonstration in February 2008 and 22nm node technology node device patterning in February 2009 using ASML's Alpha Demo Tool (ADT). In order to insert extreme ultraviolet (EUV) lithography at the 15nm technology node and beyond, we have thoroughly characterized one EUV mask, a so-called NOVACD mask. In this paper, we report on three topics, The first topic is an analysis of line edge roughness (LER) using a mask Scanning Electron Microscope (SEM), an Atomic Force Microscope (AFM) and the Actinic Inspection Tool (AIT) to compare resist images printed with the ASML ADT. The results of the analysis show a good correlation between the mask AFM and the mask SEM measurements, However, the resist printing results for the isolated space patterns are slightly different. The cause ofthis discrepancy may be resist blur, image log slope and SEM image quality and so on. The second topic is an analysis of mask topography using an AFM and relative reflectivity of mirror and absorber surface using the AIT, The AFM data show 6 and 7 angstrom rms roughness for mirror and absorber, respectively. The reflectivity measurements show that the mirror reflects EUV light about 20 times higher than absorber. The last topic is an analysis of a 32nm technology node SRAM cell which includes a comparison of mask SEM image, AIT image, resist image and simulation results. The ADT images of the SRAM pattern were of high quality even though the mask patters were not corrected for OPC or any EUV-specific effects. Image simulation results were in good agreement with the printing results.
Date: June 25, 2009
Creator: Mizuno, H.; McIntyre, G.; Koay, C.-W.; Burkhardt, M.; He, L.; Hartley, J. et al.
Partner: UNT Libraries Government Documents Department

Collecting EUV mask images through focus by wavelength tuning

Description: Using an extreme-ultraviolet (EUV) microscope to produce high-quality images of EUV reticles, we have developed a new wavelength tuning method to acquire through-focus data series with a higher level of stability and repeatability than was previously possible. We utilize the chromatic focal-length dependence of a diffractive Fresnel zoneplate objective lens, and while holding the mask sample mechanically still, we tune the wavelength through a narrow range, in small steps. In this paper, we demonstrate the method and discuss the relative advantages that this data collection technique affords.
Date: February 23, 2009
Creator: Goldberg, Kenneth A.; Mochi, Iacopo & Huh, Sungmin
Partner: UNT Libraries Government Documents Department

Using aberration test patterns to optimize the performance of EUV aerial imaging microscopes

Description: The SEMATECH Berkeley Actinic Inspection Tool (AIT) is a prototype EUV-wavelength zoneplate microscope that provides high quality aerial image measurements of EUV reticles. To simplify and improve the alignment procedure we have created and tested arrays of aberration-sensitive patterns on EUV reticles and we have compared their images collected with the AIT to the expected shapes obtained by simulating the theoretical wavefront of the system. We obtained a consistent measure of coma and astigmatism in the center of the field of view using two different patterns, revealing a misalignment condition in the optics.
Date: June 16, 2009
Creator: Mochi, Iacopo; Goldberg, Kenneth A.; Miyakawa, Ryan; Naulleau, Patrick; Han, Hak-Seung & Huh, Sungmin
Partner: UNT Libraries Government Documents Department

Acid-Base Interactions at the Molecular Level: Adhesion and Friction Studies with Interfacial Force Microscopy

Description: To examine the forces of acid-base adhesive interactions at the molecular level, we utilize the scanning probe Interracial Force Microscope (IFM). Unlike cantilever-based atomic force microscopes, the EM is a non-compliant, mechanically stable probe that provides a complete adhesive profile without jump-to-contact. In this way, we are able to quantitatively measure the work of adhesion and bond energies at well-defined, nanometer-scale single asperity contacts. In particular, we will discuss the displacement-controlled adhesive forces between self-assembled monolayer of functionalized alkanethiols strongly bound to a gold substrate and a similarly functionalized tip. We also discuss a method utilizing decoupled lateral and normal force sensors to simultaneously observe the onset of both friction and chemical bond formation. Measurements show that friction can be directly attributed to bond formation and rupture well before repulsive contact.
Date: December 9, 1998
Creator: Burns, A.R.; Carpick, R.W.; Houston, J.E. & Michalske, T.A.
Partner: UNT Libraries Government Documents Department

Comment on "Modification of graphene properties due to electron-beam irradiation"

Description: This article gives comment to a previous article entitled 'Modification of graphene properties due to electron-beam irradiation'. These articles discuss the modification of graphene properties due to electron-beam irradiation.
Date: December 17, 2009
Creator: Jones, Jason D.; Ecton, Philip A.; Mo, Yudong & Pérez, José M.
Partner: UNT College of Arts and Sciences

Tools for Nanotechnology Education Development Program

Description: The overall focus of this project was the development of reusable, cost-effective educational modules for use with the table top scanning electron microscope (TTSEM). The goal of this project's outreach component was to increase students' exposure to the science and technology of nanoscience.
Date: September 27, 2010
Creator: Moore, Dorothy
Partner: UNT Libraries Government Documents Department

X-ray stereo microscopy for investigation of dynamics in soils

Description: The presented combination of stereo imaging and elemental mapping with soft X-ray microscopy reveals the spatial arrangement of naturally aqueous colloidal systems, e.g. iron oxides in soil colloid clusters. Changes in the spatial arrangement can be induced by manipulating the sample mounted to the X-ray microscope and thus be investigated directly.
Date: September 16, 2008
Creator: Gleber, S.-C.; Sedlmair, J.; Bertilson, M.; von Hofsten, O.; Heim, S.; Guttmann, P. et al.
Partner: UNT Libraries Government Documents Department

Scaling Behavior of the First Arrival Time of a Random-Walking Magnetic Domain

Description: We report a universal scaling behavior of the first arrival time of a traveling magnetic domain wall into a finite space-time observation window of a magneto-optical microscope enabling direct visualization of a Barkhausen avalanche in real time. The first arrival time of the traveling magnetic domain wall exhibits a nontrivial fluctuation and its statistical distribution is described by universal power-law scaling with scaling exponents of 1.34 {+-} 0.07 for CoCr and CoCrPt films, despite their quite different domain evolution patterns. Numerical simulation of the first arrival time with an assumption that the magnetic domain wall traveled as a random walker well matches our experimentally observed scaling behavior, providing an experimental support for the random-walking model of traveling magnetic domain walls.
Date: February 4, 2008
Creator: Im, M.-Y.; Lee, S.-H.; Kim, D.-H.; Fischer, P. & Shin, S.-C.
Partner: UNT Libraries Government Documents Department

Friction Anisotropy: A unique and intrinsic property of decagonal quasicrystals

Description: We show that friction anisotropy is an intrinsic property of the atomic structure of Al-Ni-Co decagonal quasicrystals and not only of clean and well-ordered surfaces that can be prepared in vacuum [J.Y. Park et al., Science (2005)]. Friction anisotropy is manifested both in nanometer size contacts obtained with sharp atomic force microscope (AFM) tips as well as in macroscopic contacts produced in pin-on-disc tribometers. We show that the friction anisotropy, which is not observed when an amorphous oxide film covers the surface, is recovered when the film is removed due to wear. Equally important is the loss of the friction anisotropy when the quasicrystalline order is destroyed due to cumulative wear. These results reveal the intimate connection between the mechanical properties of these materials and their peculiar atomic structure.
Date: June 25, 2008
Creator: Mulleregan, Alice; Park, Jeong Young; Salmeron, Miquel; Ogetree, D.F.; Jenks, C.J.; Thiel, P.A. et al.
Partner: UNT Libraries Government Documents Department

3D optical sectioning with a new hyperspectral confocal fluorescence imaging system.

Description: A novel hyperspectral fluorescence microscope for high-resolution 3D optical sectioning of cells and other structures has been designed, constructed, and used to investigate a number of different problems. We have significantly extended new multivariate curve resolution (MCR) data analysis methods to deconvolve the hyperspectral image data and to rapidly extract quantitative 3D concentration distribution maps of all emitting species. The imaging system has many advantages over current confocal imaging systems including simultaneous monitoring of numerous highly overlapped fluorophores, immunity to autofluorescence or impurity fluorescence, enhanced sensitivity, and dramatically improved accuracy, reliability, and dynamic range. Efficient data compression in the spectral dimension has allowed personal computers to perform quantitative analysis of hyperspectral images of large size without loss of image quality. We have also developed and tested software to perform analysis of time resolved hyperspectral images using trilinear multivariate analysis methods. The new imaging system is an enabling technology for numerous applications including (1) 3D composition mapping analysis of multicomponent processes occurring during host-pathogen interactions, (2) monitoring microfluidic processes, (3) imaging of molecular motors and (4) understanding photosynthetic processes in wild type and mutant Synechocystis cyanobacteria.
Date: February 1, 2007
Creator: Nieman, Linda T.; Sinclair, Michael B.; Davidson, George S.; Van Benthem, Mark Hilary; Haaland, David Michael; Timlin, Jerilyn Ann et al.
Partner: UNT Libraries Government Documents Department

Fastest Electropolishing Technique on Niobium for Particle Accelerators

Description: Field emission on the inner surfaces of niobium (Nb) superconducting radio frequency (SRF) cavities is still one of the major obstacles for reaching high accelerating gradients for SRF community. Our previous experimental results [1] seemed to imply that the threshold of field emission was related to the thickness of Nb surface oxide layers. In this contribution, a more detailed study on the influences of the surface oxide layers on the field emission on Nb surfaces will be reported. By anodization technique, the thickness of the surface pentoxide layer was artificially fabricated from 3nm up to 460nm. A home-made scanning field emission microscope (SFEM) was employed to perform the scans on the surfaces. Emitters were characterized using a scanning electron microscope together with an energy dispersive x-ray analyzer. The experimental results could be understood by a simple model calculation based on classic electromagnetic theory as shown in Ref.1. Possibly implications for Nb SRF cavity applications from this study will be discussed.
Date: September 1, 2011
Creator: A.T. Wu, S. Jin, R.A. Rimmer, X.Y. Lu, K. Zhao
Partner: UNT Libraries Government Documents Department

Evaluating EUV mask pattern imaging with two EUV microscopes

Description: Aerial image measurement plays a key role in the development of patterned reticles for each generation of lithography. Studying the field transmitted (reflected) from EUV masks provides detailed information about potential disruptions caused by mask defects, and the performance of defect repair strategies, without the complications of photoresist imaging. Furthermore, by measuring the continuously varying intensity distribution instead of a thresholded, binary resist image, aerial image measurement can be used as feedback to improve mask and lithography system modeling methods. Interest in EUV, at-wavelength, aerial image measurement lead to the creation of several research tools worldwide. These tools are used in advanced mask development work, and in the evaluation of the need for commercial at-wavelength inspection tools. They describe performance measurements of two such tools, inspecting the same EUV mask in a series of benchmarking tests that includes brightfield and darkfield patterns. One tool is the SEMATECH Berkeley Actinic Inspection Tool (AIT) operating on a bending magnet beamline at Lawrence Berkeley National Laboratory's Advanced Light Source. The AIT features an EUV Fresnel zoneplate microscope that emulates the numerical aperture of a 0.25-NA stepper, and projects the aerial image directly onto a CCD camera, with 700x magnification. The second tool is an EUV microscope (EUVM) operating at the NewSUBARU synchrotron in Hyogo, Japan. The NewSUBARU tool projects the aerial image using a reflective, 30x Schwarzschild objective lens, followed by a 10-200x x-ray zooming tube. The illumination conditions and the imaging etendue are different for the two tools. The benchmarking measurements were used to determine many imaging and performance properties of the tools, including resolution, modulation transfer function (MTF), aberration magnitude, aberration field-dependence (including focal-plane tilt), illumination uniformity, line-edge roughness, and flare. These measurements reveal the current state of the art in at-wavelength inspection performance, and will be a useful reference as ...
Date: February 26, 2008
Creator: Goldberg, Kenneth A.; Takase, Kei; Naulleau, Patrick P.; Han, Hakseung; Barty, Anton; Kinoshita, Hiroo et al.
Partner: UNT Libraries Government Documents Department

In situ nanoindentation in a transmission electron microscope

Description: This dissertation presents the development of the novel mechanical testing technique of in situ nanoindentation in a transmission electron microscope (TEM). This technique makes it possible to simultaneously observe and quantify the mechanical behavior of nano-scale volumes of solids.
Date: December 2, 2002
Creator: Minor, Andrew M.
Partner: UNT Libraries Government Documents Department

Standard Test Specimens of Zinc Bronze (Cu 88, Sn 10, Zn 2) - Parts 1 and 2: Part 1. - Preparation of Specifications, Part II. - Microstructure

Description: Technical paper issued by the Bureau of Standards over tests conducted on the preparation of an alloy. The tests conducted, and their results are presented and discussed. This paper includes tables, illustrations, and photographs.
Date: March 15, 1916
Creator: Karr, C. P. & Rawdon, Henry S.
Partner: UNT Libraries Government Documents Department

Up-conversion time microscope demonstrates 103x magnification of an ultrafast waveforms with 300 fs resolution

Description: We have demonstrated a system for the temporal expansion of arbitrarily shaped ultrafast optical waveforms based on the principle of temporal imaging. This system has demonstrated 103x magnification of an input signal with 300 fs resolution, thus allowing ultrafast phenomena to be recorded with slower conventional technology. The physics of temporal imaging work on a single shot basis, thus it is expected that this technology will lead to a new class of single transient recorders with ultrafast resolution.
Date: October 17, 1998
Creator: Bennett, C. V. & Kolner, B. H.
Partner: UNT Libraries Government Documents Department

Quantitative in situ nanoindentation of aluminum films

Description: We report the development of a method for quantitative, in situ nanoindentation in an electron microscope and its application to study the onset of deformation during the nanoindentation of aluminum films. The load-displacement curve developed during in situ nanoindentation shows the characteristic ''staircase'' instability at the onset of plastic deformation. The instability corresponds to the first appearance of dislocations in previously defect-free grains, and occurs at a force near that measured in conventional nanoindentation experiments on similarly oriented Al grains. Plastic deformation proceeds through the formation and propagation of prismatic loops punched into the material, and half-loops that emanate from the sample surface. This new experimental technique permits the direct observation of the microstructural mechanisms that operate at the onset of deformation.
Date: April 4, 2001
Creator: Minor, Andrew M.; Stach, Eric A. & Morris, J. W., Jr.
Partner: UNT Libraries Government Documents Department

EUV pattern defect detection sensitivity based on aerial image linewidth measurements

Description: As the quality of EUV-wavelength mask inspection microscopes improves over time, the image properties and intensity profiles of reflected light can be evaluated in ever-greater detail. The SEMATECH Berkeley Actinic Inspection Tool (AIT) is one such microscope, featuring mask resolution values that match or exceed those available through lithographic printing in current photoresists. In order to evaluate the defect detection sensitivity of the AIT for dense line patterns on typical masks, the authors study the line width roughness (LWR) on two masks, as measured in the EUV images. They report the through-focus and pitch dependence of contrast, image log slope, linewidth, and LWR. The AIT currently reaches LWR 3{sigma} values close to 9 nm for 175 nm half-pitch lines. This value is below 10% linewidth for nearly all lines routinely measured in the AIT. Evidence suggests that this lower level may arise from the mask's inherent pattern roughness. While the sensitivity limit of the AlT has not yet been established, it is clear that the AIT has the required sensitivity to detect defects that cause 10% linewidth changes in line sizes of 125 nm and larger.
Date: February 12, 2010
Creator: Goldberg, K. A.; Mochi, I.; Naulleau, P.; Liang, T.; Yan, P.-Y. & Huh, S.
Partner: UNT Libraries Government Documents Department

A comparison of DNA damage probes in two HMEC lines with X-irradiation

Description: In this study, we investigated {gamma}H2AX{sup ser139} and 53BP1{sup ser25}, DNA damage pathway markers, to observe responses to radiation insult. Two Human Mammary Epithelial Cell (HMEC) lines were utilized to research the role of immortalization in DNA damage marker expression, HMEC HMT-3522 (S1) with an infinite lifespan, and a subtype of HMEC 184 (184V) with a finite lifespan. Cells were irradiated with 50 cGy X-rays, fixed with 4% paraformaldehyde after 1 hour repair at 37 C, and processed through immunofluorescence. Cells were visualized with a fluorescent microscope and images were digitally captured using Image-Pro Plus software. The 184V irradiated cells exhibited a more positive punctate response within the nucleus for both DNA damage markers compared to the S1 irradiated cells. We will expand the dose and time course in future studies to augment the preliminary data from this research. It is important to understand whether the process of transformation to immortalization compromises the DNA damage sensor and repair process proteins of HMECs in order to understand what is 'normal' and to evaluate the usefulness of cell lines as experimental models.
Date: January 19, 2007
Creator: Wisnewski, Christy L.; Bjornstad, Kathleen A.; Rosen, ChristoperJ.; Chang, Polly Y. & Blakely, Eleanor A.
Partner: UNT Libraries Government Documents Department

Carbon contamination of extreme ultraviolet (EUV) mask and its effect on imaging

Description: Carbon contamination of extreme ultraviolet (EUV) masks and its effect on imaging is a significant issue due to lowered throughput and potential effects on imaging performance. In this work, a series of carbon contamination experiments were performed on a patterned EUV mask. Contaminated features were then inspected with a reticle scanning electron microscope (SEM) and printed with the SEMA TECH Berkeley Microfield-Exposure tool (MET) [1]. In addition, the mask was analyzed using the SEMA TECH Berkeley Actinic-Inspection tool (AIT) [2] to determine the effect of carbon contamination on the absorbing features and printing performance. To understand the contamination topography, simulations were performed based on calculated aerial images and resist parameters. With the knowledge of the topography, simulations were then used to predict the effect of other thicknesses of the contamination layer, as well as the imaging performance on printed features.
Date: February 2, 2009
Creator: Fan, Yu-Jen; Yankulin, Leonid; Antohe, Alin; Garg, Rashi; Thomas, Petros; Mbanaso, Chimaobi et al.
Partner: UNT Libraries Government Documents Department