AVS2010 Session AS-TuP: Applied Surface Science Poster Session

Tuesday, October 19, 2010 6:00 PM in Southwest Exhibit Hall

Tuesday Evening

Time Period TuP Sessions | Topic AS Sessions | Time Periods | Topics | AVS2010 Schedule

AS-TuP-1 Application of an Electrospray Technique to Secondary Ion Mass Spectrometry (SIMS)
Yukio Fujiwara, Naoaki Saito, Hidehiko Nonaka, Taisuke Nakanaga, Shingo Ichimura (National Institute of Advanced Industrial Science and Technology (AIST), Japan)

An electrospray technique can generate a continuous stream of charged droplets at currents exceeding 1000 nA. We expect that it has a great potential in Secondary Ion Mass Spectrometry (SIMS). Consequently, we investigated beam generation characteristics using the electrospray technique operated at atmospheric pressure and under reduced pressure (i.e., vacuum).

When electrospraying is performed at atmospheric pressure or above, emitted charged droplets and ions are required to be sampled through an aperture into a vacuum chamber, and then accelerated toward a target. It was confirmed that a beam current was considerably reduced in the process passing through the aperture; for instance, passing efficiency through the 120-mm aperture was on the order of 10-3. This loss mainly results from the spreading of electrosprayed ions at atmospheric pressure.

When electrospraying is done in a vacuum, freeze and evaporation of a solution will be a serious problem. In other words, in the case of frequently-used solutions such as water and ethanol, it is difficult to achieve stable electrospraying in a vacuum because of the freeze and evaporation around a capillary tip. To solve the problem, we have proposed a vacuum electrospray beam source using pure ionic liquids for SIMS application. Ionic liquids have very low vapor pressure as well as high ionic condu ctivity; its use will ena ble us to perform stable electrospraying in a vacuum. We investigated the electrospray characteristics of an ionic liquid in a high vacuum environment with pressures around 10-5 Pa using the stainless-steel capillary. The experimental results demonstrated that stable electrosprayed currents of the order of 1000 nA can be continuously generated in both positive and negative modes. Experimental results indicate that the electrospray technique seems to be applicable to SIMS.

AS-TuP-2 Structure and Chemical Composition of Thiol-SAMs on Au Surfaces for Biological Applications
Michael Bruns, Sinem Engin, Vanessa Trouillet, Doris Wedlich (Karlsruhe Institute of Technology, Germany); Philipp Brüner, Thomas Grehl, Sven Kayser (ION-TOF GmbH, Germany); Paul Mack, Richard G. White (ThermoFisher Scientific, UK)
Structured and oriented immobilization of bio-molecules has become subject of great interest in recent years due to the expected diversity of applications, e.g. bio sensors in diagnosis, lab-on-chip technology, and modern cell culture focused on cell adhesion, migration, and differentiation. Therefore, a lot of effort has been spent to develop strategies for covalent and non-covalent immobilization of proteins, respectively. A very promising approach is surface patterning by micro-contact printing (µCP) to produce self-assembled-monolayers (SAMs) on gold surfaces based on mixtures of benzylguanine thiol (BGT) and matrix thiol. In this case BGT is the substrate for the SNAP-tag system, allowing for covalent attachment of any protein of interest fused to this tag, whereas the inert matrix thiol acts as spacer for BGT and moreover prevents from non-specific protein adsorption.1
The present contribution focuses on the characterization of pure benzylguanine and matrix thiols as well as mixtures of both using a combination of complementary surface analytical methods. For this purpose all SAMs were prepared on gold films deposited onto glass substrates by r. f. magnetron sputtering directly prior to the thiol exposure. The chemical composition and the covalent binding of the thiols were proved by time-of-flight secondary ion mass spectrometry (ToFSIMS) and X-ray photoelectron spectroscopy (XPS) as well. The orientation of the SAMs together with thickness information were achieved by high-sensitive low-energy ion scattering (LEIS),2and were justified by non-destructive depth profiles reconstructed from parallel angle-resolved XPS data applying a maximum entropy algorithm. Finally the µCP micro-structures were verified by ToFSIMS.
  1. S. Engin, V. Trouillet, C. M. Franz, A. Welle, M. Bruns, and D. Wedlich, Benzylguanine Thiol Self-Assembled Monolayers for Immobilization of SNAP-tag Proteins on Microcontact printed Surface Structures, Langmuir, DOI: 10.1021/la904829y.
  2. H. H. Brongersma, Th. Grehl, P. A. van Hal, N. C. W. Kuijpers, S. G. J. Mathijssen, E. R. Schofield, R. A.P. Smith, H. R.J. ter Veen, High-sensitivity and high-resolution low-energy ion scattering, Vacuum 84 (2010) 1005-7.
AS-TuP-3 Thickness and Composition of the HfO2/Si Interface Layer As a Function of Aperture-Time of Oxidant-Agent for ALD-grown HfO2 Nanofilms
Pierre Giovanni Mani-Gonzalez, Milton Oswaldo Vazquez-Lepe, Alberto Herrera-Gomez (CINVESTAV Queretaro, Mexico)
Hafnium oxide nanofilms were grown with ALD (Atomic Layer Deposition) on H-terminated Si(001) wafers employing TDMA-Hf (tetrakis dimetil animo hafnium) and water as precursors. The structure of the films was characterized with angle-resolved X-ray photoelectron spectroscopy (ARXPS). While the aperture-time for TDMA-Hf was kept constant at 0.08 s during the ALD deposition, the aperture-time (t H2O) for the oxidant-agent (H2O) was varied from 0 to 0.1 s among the different samples. The water exposition-time has a direct effect on the thickness of the HfO2 layer, which saturates at ~ 1.7 nm for 30-cycle ALD processes. The composition and thickness of the interface between Si and hafnia is approximately constant at Hf0.5Si0.5O2 and 1 nm for 0.02 < t H2O <0.06 s. For larger aperture-times, the Hf contribution to the composition rises slowly; the thickness of the layer also rises slowly. The total film thickness, including the hafnium silicate and hafnium oxide layers, saturates at ~ 3 nm. Our results are in accordance with prior results, which estimate the film growth rate at ~ 1 Å per ALD cycle.
AS-TuP-4 Defect States in Amorphous GaInZnO Thin Film Grown on SiO2/Si Substrates
Sung Heo, Jae Gwan Chung, Hyung-Ik Lee, Eun Ha Lee, Jae Cheol Lee, Gyeong Su Park (Samsung Advanced Institute of Technology, Korea); Jong Soo Oh, Hoon Young Cho (Dongguk University, Korea); Dahlang Tahi, Lee Seul Son, Suhk Kun Oh, Hee Jae Kang (Chungbuk National University, Korea); T. Nagatomi, Y. Takai (Osaka University, Japan)

Transparent oxide conductor and semiconductor are useful for us to develop electronic components in various applications such as flat panel display and solar cells. In particular, amorphous Ga-In-Zn-O (a-GIZO) thin films are promising channel materials for thin film transistors (TFTs) because a-GIZO TFTs exhibit large field-effect mobility (>10 cm2/V s) irrespective of their fabrication on various substrates, such as silicon, glass, plastic, polyimide, polyethylene terephthalate (PET), cellulose paper and flexible substrates. In addition, they have superior uniformity, low processing temperature, possibility of large-area deposition and long term stability, and moreover they are cost effective.

In recent years, a large progress has been made in high performance TFTs based on a-GIZO as channel layers. Amorphous semiconductors have defect states originating from structural disorder and defect, which strongly affect carrier transport properties and devices performances. However, fundamental material properties of a-GIZO such as the band alignment and defect states, which are important for devices structure and circuit configuration have not been investigated in detail so far. Moreover, any investigation of band alignment and defect states of a-GIZO thin films is very important to understand the transport mechanism and to improve device performances.

In this study, we have investigated the band gap, valence band offset and defect states of GIZO thin films by using reflection electron energy loss spectroscopy (REELS), X-ray photoelectron spectroscopy (XPS), thermally stimulated exo-electron emission (TSEE) and photoinduced current transient spectroscopy (PICT). The band gap and valence band offset (VBO or △EV) allow us to determine the conduction band offset △EC) by using the relation: △EC = Eg(SiO2) - △EV (GIZO/SiO2/Si) - Eg(a-GIZO). The band gap is 3.2eV, and the conduction band offset of GIZO is 3.62 eV. The shallow defect states obtained via PICT were at 0.24eV and 0.53eV below the conduction band minimum of a-GIZO thin film, and the deep defect state obtained by means of TSEE is 1.827eV below the conduction band minimum of GIZO thin film.

AS-TuP-5 Band Alignment and Defect States in Amorphous Si-N Compounds on Si Substrates
Hyung-Ik Lee (Samsung Advanced Institute of Technology)

Silicon nitride (SiNx) has an important application in the photovoltaics. First, plasma SiN films have provided effective surface passivation of silicon solar cells. Secondly, SiN has an important application in electronic memory devices. The memory property of the amorphous silicon nitride (a-SiNx) is due to its electronic structure dominated by many deep traps.

Electronic properties of a-Si3N4 are determined mainly by deep traps of electrons and holes as well as by hollow traps responsible for the spreading of charges captured by deep traps. In other words, they are responsible for the degradation of nonvolatile memory devices based on NMOS. Because of this, a correct knowledge about the nature of levels is extremely important in selecting the technology for the preparation of layers intended for specific application.

In this study, in order to obtain band alignment as well as defect state of SiNx thin films, we have investigated the band gap and valence band offset with the variation in the composition of N contents by using reflection electron energy loss spectroscopy (REELS) and X-ray photoelectron spectroscopy (XPS), respectively. The defect states were investigated by using thermally stimulated exo-electron emission (TSEE), which have been specially designed for in-situ measurement of a defect state in analysis chamber without any electrodes.

Our result shows that the valance band offsets were increased from 0.033 eV to 1.24 eV with increasing N contents. The band gap was changed from 3.2 eV to 4.7 eV for the above materials. The defect state energy of the a-SiNx films were observed at 1.85 eV by using thermally stimulated exo-electron emission. This energy is related to hydrogen migration or a dangling bond (·Si≡), called the K center, in the silicon nitride.[1] The values of deep trap energy below the conduction band are independent of N content.[2] The defect state energy are properly assigned.

AS-TuP-9 Multi-scale Characterization Studies of Li-ion Batteries
Shrikant Nagpure, Bharat Bhushan, Sudarsanam Babu, Giorgio Rizzoni (The Ohio State University)
Advanced Li-ion batteries with high energy and power density are fast approaching compatibility with automotive demands. While the mechanism of the operation of these batteries is well understood the aging mechanisms are still under investigation. While aging at the macroscopic level is directly measurable by increase in the internal resistance, at material level that include cathode, anode, separator and electrolyte aging can be attributed to many degradation mechanisms. As, the degradation of the material is caused by several simultaneous physiochemical processes that occur within the batteries, material characterization in automotive application batteries is a challenging task. We have identified and tested a set of experimental techniques for multi-scale characterization of the cathode in the Li-ion batteries. The electrical properties are studied using the electrochemical impedance spectroscopy and scanning spreading resistance microscopy. The structural degradation is studied using the infrared thermal imaging (meters), scanning electron microscope (micro), X-ray diffraction (micro), atomic force microscope (micro to nano), transmission electron microscope (micro) and electron energy loss spectroscopy. Finally, a relatively new neutron depth profiling technique was successfully used in these studies to study the transport and concentration of lithium within the few microns of the cathode thickness. We present the results obtained from this set of experiments when applied to the samples extracted from an unaged and an aged LiFePO4 based Li-ion battery.
AS-TuP-10 Improved Tougaard Background Calculation using Predetermined Inelastic Electron Scattering Cross Section Functions K(T) using the Software UNIFIT 2011
Ronald Hesse, Reinhard Denecke (Universität Leipzig, Germany)

The shape of the background in x-ray photoemission spectra may be affected by secondary electrons and inelastic energy loss processes. A polynomial of low order has very often turned out to model the secondary electron background. The Tougaard background model [1] has been successfully used to characterise the inelastic loss processes. However, the correct usage of the Tougaard background needs a well defined K(T) function (T = energy loss). The introduction of a four parameter loss function K(T) = BT/(C-C’T²)²+DT² with the fitting parameters B, C, C’ and D implemented in the fittable background function [2] allows the improved estimation of the K(T) function. The results will be compared with the recommended parameters by Tougaard. The calculation of inelastic electron scattering cross sections of clean surfaces from different materials using UNIFIT will be demonstrated.

[1] S. Tougaard, Surf. Interface Anal. 25 (1997) 137

[2] R. Hesse, T. Chassé, R. Szargan, Fresenius J. Anal. Chem., 365 (1999) 48

AS-TuP-11 Comparative Study of Two Different Methods for Film Thickness Determination on Model and Real Systems using the Software UNIFIT 2010
Ronald Hesse, Peter Streubel, Reinhard Denecke (Universität Leipzig, Germany)

The accuracy of thickness determination of laterally homogenous films by XPS in the range of few nm may be improved by combining two different methods. The results of the well established angle resolved photoelectron spectroscopy (ARXPS) for determining film thicknesses will be compared with the ones determined using the relative quantification of photoelectron lines at two different kinetic energies (i.e. energy-resolved) and the same emission angle (ERXPS). Only the substrate intensities were used. The advantages and disadvantages of both methods will be shown. The reliability and accuracy of the thickness determination by the two different methods is discussed for suitable model and real systems. The easy handling of the data analysis for estimating film thicknesses using UNIFIT will be demonstrated.

AS-TuP-13 MVSA Analysis of 3D MCs+ ToF-SIMS Data
Vincent Smentkowski (GE Global Research Center); Michael Keenan (Consultant)

Depth profiling via ToF-SIMS is a well established technique that is used to determine the depth distribution of trace species in samples. 3D depth profiling techniques are now being heavily utilized in the ToF-SIMS community since it enables the measurement of both the depth distribution and the lateral distribution of the species. 3D ToF-SIMS analysis are revealing that many samples are not uniform in the lateral dimension. Since a full mass spectrum is saved at every volume element, unexpected species are often found sub-surface, especially in real-world sample. Unfortunately, one often needs to perform two depth profile measurements in order to fully characterize a sample – a positive ion measurement to look for electropositive species with the highest sensitivity and a negative ion measurement in order to analyze electronegative species with the highest sensitivity. The two depth profile measurements are often performed using different erosion sources and experimental conditions which have been optimized for the species to be analyzed and often have significant differences in the erosion rate. Since the analysis are performed in two different regions of the sample, one can not correlate species observed in the two independent measurements. Additionally, there are instances where the amount of material is limited and one can not perform two measurements. MCs+ analysis have been reported in the ToF-SIMS literature. For MCs+ analysis one uses a Cs+ ion beam to erode the sample, and a Bi3+ ion beam to perform the analysis in the positive ion polarity. Electropositive species are detected as M+ and/or M+Cs+ and the electronegative species are detected as M+ and/or M+Cs2+ (where M is the element being analyzed). In this paper, we will demonstrate, for the first time, the ability to analyze complicated 3D MCs+ ToF-SIMS data sets using MVSA techniques. We will show the advantages of MVSA analysis over univariate analysis.

AS-TuP-14 Metal Silicide Nanoscale Chemical Characterization with Scanning Auger Microscopy
Dennis F. Paul, John S. Hammond, David G. Watson (Physical Electronics)

Scanning Auger Microscopy is a powerful compositional analysis technique for surfaces and nanostructures. It is well known that Auger instruments based on full CMA analyzers provide a stable imaging platform and analytical capability that can be successfully applied to a wide range of material systems. Recently a high energy resolution spectroscopy mode that provides enhanced chemical characterization was added to a CMA Auger instrument. This new functionality is integrated with the instrument while maintaining all the existing capabilities and benefits associated with the CMA based Auger instrument.

The usefulness of this new high energy resolution spectroscopy mode will be demonstrated with detailed chemical information from annealed metal silicide ultra thin films on silicon wafers. Low energy ion beam depth profiling facilitates a chemical state evaluation of the silicide/wafer interface induced by the annealing process. Auger mapping and high energy resolution Auger spectroscopy also characterizes the three dimensional nanostructures formed on the surface and at the interfaces of these metal silicide ultra thin films.

AS-TuP-15 Influences Finish Quality in Machining Austempered Ductile Iron
Wilmar Mattes (SENAI-SC, Brazil); Alex C. Bottene (LOPF/NUMA, Brazil); Ramon da Silva (UNERJ, Brazil)
The austempered cast iron (ADI - Austempered Ductile Iron), has been successfully applied in diesel trucks, class 8 trucks and agricultural tractors power train parts. This material has also been used in high performance gears, applied in various segments of the mechanical industry, especially in the automotive field because of their properties and technical advantages associated to the combination of strength and ductility of the material. The main technical limitation of the ADI is attributed to its machinability. This problem is related to the hardening that occurs by the transformation of austenite, characteristic of the microstructure of austempered ductile, which affects the steps of the production process and achieve common cropping the part before the heat treatment and finish machining right after them. This paper discusses a study on the behavior of the surface finish quality, technical and financial feasibility of the machining process. Comparing the use of grinding, CBN wheel, and the hard turning operation, cemented carbide coated TiAlCrN, of ADI by comparative analysis of lifetime of the tools in terms of speed of cutting, using as a criterion to end the life of the tool flank wear of 0.3 mm.
AS-TuP-18 XPS Analysis of Surface Films Formed on Common Metals on Exposure to Ethanol-Blended Fuels
Harry M. Meyer III, Steven J. Pawel (Oak Ridge National Laboratory)
Most automobile fuels contain some amount of ethanol, typically around 10% by volume, and fuels with higher ethanol levels are available. In Brazil mandated ethanol levels are 25% (E25 fuel) and in 2009 over 9 million vehicles were on the road using pure ethanol (E100) as fuel. Certainly, in the years ahead increasing levels of ethanol will be available in US fuels. As such, most automobile manufacturers are producing engines that can handle a variety of ethanol-blends. This poster examines several common metals used in fuel storage and fuel handing equipment, namely brass, galvanized steel, and nickel, and compares unexposed material to material that has been exposed to (1) reference gasoline and (2) E10 fuel and (3) E25 fuel. Samples were cleaned (acetone + ultrasonic), weighed, and placed in a stainless steel vessel. Fuel was added and the vessel was purged with Ar and sealed. After raising the temperature to 60 C, the samples were left for 28 days. Upon removal, the samples were rinsed with pure ethanol, dried, and weighed. X-ray photoelectron spectroscopy was used for determining surface composition. Sputter profiling was used to monitor changes in composition as a function of depth. For some samples, XPS mapping was employed to determine lateral distribution of chemical species. Results presented in this poster clearly show greater oxidation and the formation of metal sulfide species for the ethanol-blended fuels as compared to the reference gasoline. Increasing the ethanol content above E10 to E17 showed an increase in the extent of oxidation and formation of metal sulfides.
AS-TuP-19 Sputtering of Lunar Regolith Simulant by Singly and Multicharged Constituents of the Solar Wind
Fred W. Meyer, Peter R. Harris, Harry M. Meyer III (Oak Ridge National Laboratory); Nasser Barghouty, James H. Adams, Jr. (Marshall Space Flight Center NASA)
We report preliminary results on sputtering of a lunar regolith simulant sample by H+, Ar+, Ar6+ and Ar9+ at solar wind-relevant energies. Such interactions are an important determinant of lunar exosphere composition, and may provide a possible pathway leading to the production of water on the moon. The presence of lunar water was recently confirmed by a number of orbiting lunar missions. The ions are generated using an electron cyclotron resonance (ECR) ion source at source potentials between 10-15kV. After being extracted, transported, and decelerated, the ions are normally incident on a pressed lunar regolith simulant sample that is situated within a floating UHV scattering chamber. The relative bias between the ECR source and the surface end station was adjusted to produce a constant impact energy of 0.375keV/amu for each of the 4 ion beams investigated. To simulate the effect of the dominant proton component, which constitutes >90% of the solar wind, the lunar regolith simulant sample was prepared by exposure to a proton beam up to total fluences of ~2x1018 H+/cm2 prior to each of the Ar beam sputtering runs. Both transient and steady state conditions of sputtered species were monitored by a quadrupole mass spectrometer situated within the UHV scattering chamber. SEM and XPS analyses of the JSC-1A AGGL simulant were performed to monitor possible changes in surface morphology and composition during the pressing of the loose powder into the sample holder.
AS-TuP-20 Chemical Depth Profiling: Relating Interfacial and Sub-surface Characterization to Electrical Performance
Kathryn G. Lloyd, Lei Zhang, John P. Wyre, James R. Marsh, Mark A. Plummer (DuPont Corporate Center for Analytical Sciences)

Thin multi-layered structures form the basis for photovoltaic/solar cells, OLED displays, and many other electronic devices. Electrical performance can be influenced by the thickness of these layers, the widths of interfaces between layers and/or development of interfacial chemistry, and the extent and location of dopants within layers. Depth profiling, i.e., obtaining chemical information as a function of dpeth, can provide this information, especially for systems wehre cross-sectioning is not an option, species of interest are present below 1%, or sampling with better than 1 micron depth resolution is required.

ToF-SIMS (Time-of-Flight Secondary Ion Mass Spectrometry) and X-ray Photoelectron Spectroscopy (XPS, a.k.a. ESCA) are typically used in conjunction with a high-current ion sputter beam to analyze the outermost surfaces as they are freshly revealed. ToF-SIMS depth profiling offers high mass resolution, spatially-resolved chemical information, and the collection of the entire mass spectrum at each depth interval. The combination of ToF-SIMS depth profiling and multivariate methods of data analysis allows better definition and characterization of interfacial regions between layers.

Examples include characterization of the BSF (back surface field) layer on solar cell backsides, monitoring layered oxide growth on annealed stainless steels, and study of interdiffusion in organic electronic layered structures.

AS-TuP-21 In-situ XPS Analysis of Co and Co2+ during Steam Reforming of Ethanol on Supported Cobalt Catalysts
Ayman Karim, Yu Su, Mark H. Engelhard, David King, Yong Wang (Pacific Northwest National Laboratory)

In catalysis, the oxidation state of metal nanoparticles on the surface is often unknown, especially under oxidizing conditions. The redox properties of the catalyst are typically investigated by temperature programmed reduction and oxidation or x-ray absorption spectroscopy. However, these are not the surface sensitive techniques and provide limited surface details especially under H2/H2O environments. We report the use of in-situ x-ray photoelectron spectroscopy (XPS) to determine the oxidation state of Co following exposure to O2, H2, and H2/H2O. We found that the type of support and catalyst pretreatment (calcinations and/or reduction temperature) have a strong effect on the Co0/Co2+ ratio. Our results indicate that Zn helps stabilize Co against oxidation by O2 or H2O. The in-situ XPS measurements allowed us to study the effect of Co0/Co2+ ratio on the catalytic activity and understand the role of Co2+ in the ethanol reforming reaction pathways. The catalytic tests show that both Co0 and Co2+ were active in the C-C bond cleavage and water gas shift reactions. However, Co0 is shown to be much more active than Co2+. Also, the reaction pathways for CO2 and CH4 formation appear to be different on Co0 and Co2+. Catalysts with higher Co0/Co2+ surface ratio exhibited lower selectivity to CH4. Our results show that ethanol decomposition and CO methanation are more favored on Co2+ relative to Co0. In addition, we show that on both Co0 and Co2+, CO2 is a secondary product forming by the water gas shift reaction.

AS-TuP-23 Characterization of a Self-assembled Molecular Nanolayer at Buried Cu-silica Interface
Saurabh Garg, Ranganath Teki, Ashutosh Jain, Karthik Chinnathambi, Binay Singh (Rensselaer Polytechnic Institute); Vincent Smentkowski (GE Global Research Center); Michael Lane (Emory and Henry College); Ganpati Ramanath (Rensselaer Polytechnic Institute)

Integration of metal-dielectric interfaces using molecular nanolayers (MNLs) is attractive for prospective applications such as laminates in high frequency electronics and packaging, nanodevice wiring and composites. Recent works have shown that annealing-induced siloxane bridging can toughen organosilane-functionalized copper-silica interfaces. While strong bonding of the MNL with the under- and over-layers is essential for promoting adhesion, the nature of the MNL structure and bonding, especially at temperatures where the MNLs are known to degrade on bare surfaces, are unclear. But tracking atomic-level intermixing and interfacial phase formation in a sub-nm-layer is an exacting challenge due to difficulties in distinguishing Si atoms in the organosilane MNL from Si atoms in the silica substrate, and obtaining sufficient contrast by electron microscopy. Here, we study organogermane-tailored interfaces using a combination of electron spectroscopy and microscopy, and density functional theory calculations to obtain insights into the interface chemical changes. Our results reveal that annealing decomposes the organic monolayer into an inorganic Cu-O-Si network, leading to interface toughening.

We assembled Benzyl-trichlorogermane (BTCG) on silica to form a 0.7-nm-thick nanolayer. Four-point bending fracture tests on as-prepared Cu/BTCG/SiO2 sandwiches revealed a low interface toughness of 2.1 J/m2, comparable to pristine Cu/SiO2 structures. However, interfacial toughness increased monotonically with annealing temperature, yielding values as high as 23.3 J/m2 for Tanneal­ = 500 ºC. Core-level spectra from silica fracture surfaces show a strong Ge signature for Tanneal ≤ 300 ºC that becomes undetectable for Tanneal ≥ 400 ºC, suggesting Ge transport and destruction of the organic MNL. This result is corroborated by time-of-flight secondary ion mass spectroscopy (SIMS) profiles showing the smearing of the interfacial Ge spike into the silica layer upon annealing. Incorporation of Ge in the silica weakens the Si-O-Si network, leading to intermixing of Si, O and Cu, forming nanoscale islands of rhombohedral CuSiO3 observable by cross-sectional transmission electron microscopy and X-ray spectroscopy. For pristine Cu/SiO2 structures there were no changes at the interface and the toughness value was ~ 3 J/m2 for Tanneal ≤ 700 °C. Our findings suggest that molecular degradation of the organic MNL to form nanoscopic layer of inorganic metal-oxide-silicon bonds could be an attractive approach for toughening interfaces.

AS-TuP-24 Experiences with the High Energy Resolution Optics (HERO) Update on a Physical Electronics 690 Auger System
William Wallace, James A. Ohlhausen, Michael T. Brumbach (Sandia National Laboratories)

We will present our experiences with the new High Energy Resolution Optics (HERO) upgrade on a Physical Electronics Auger 690 system. This upgrade allows the single pass cylindrical analyzer in the Auger system to achieve higher energy resolution than in the standard mode. With this upgrade, it should be possible to separate chemical states for certain elements. Also, it should be possible to separate closely spaced peaks from selected elements that have been difficult or impossible to separate without the upgrade. Specifically, we will investigate practical use of this upgrade in the analysis of materials systems where overlapping peaks have historically been an issue, such as Kovar, which consists of the elements Ni, Fe and Co. Strategies for the successful use of the technique as well as its current limitations will be shown.

§Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.

AS-TuP-25 A Device for Traceable Force Probe Calibration
Jose F. Portoles, Peter J. Cumpson (Newcastle University, UK)

AFM has become in the last two decades an instrument for the measurement of forces in the piconewton range, including forces at the single molecule level. Although many methods have been developed for the force calibration of AFM cantilevers [1], these use to be affected by high uncertainties and sometimes difficulty of use. Furthermore there is a growing need for a traceable force calibration standard that provides traceability to the units of the SI [2] and therefore allows comparison between instruments and with related force measurement techniques such as the Optical Tweezers and the Biomembrane Force Probe. We present the development of a device that provides fast and easy force calibration of AFM cantilevers and other force probes, simultaneously facilitating the dissemination of force and providing traceability to the units of the SI.

[1] J.L. Hutter and J. Bechhoefer, Rev. Sci. Instrum. 64 (7) 1993, pp. 1868-1873

[2] P.J. Cumpson and J. Hedley, Nanotechnology 14 (12) 2003, pp. 1279-1288

AS-TuP-26 Synthesis and Characterization of System Sr(Ru1-XFeX)O3 type Perovskite
Lázaro Huerta, José Luis Mazariego, Manuel Quintana (Universidad Nacional Autónoma de México); Efren Ramírez (Universidad Autónoma de la Ciudad de México); Martin Flores (Universidad de Guadalajara, México); Raul Escamilla (Universidad Nacional Autónoma de México)

Polycrystalline samples of the SrRu1-xFexO3 system with x = 0, 0.25, 0.5, 0.75 and 1.0, were synthesized by solid state reaction of stoichiometric quantities of oxides of RuO2, Fe2O3 and SrCO3. The samples were characterized by X-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS) and ac magnetization vs. temperature measurements. XRD results shown that the lattice parameter decreases with the iron content; as a consequence the unit cell volume decreases. The Sr 3d, Ru 3d Fe 3d and O 1s spectral lines associated to the chemical states of Sr(Ru1-xFex)O3 were identified by XPS. Curves of ac magnetization vs. temperature shown for x ≥ 0.25 a behavior spin glass.

AS-TuP-27 Surface Energy, Topography & Composition of SiOx on Polycarbonate by Proton-Induced X-ray Emission (PIXE), Atomic Force Microscopy & Sessile Drop Contact Angle Analysis using Young-Dupre Equation.
Qian Xing (Arizona State University); Clarizza Fiel Watson (SiO2 Associates, LLC); Murdock A. Hart, David A. Sell, James D. Bradley, Robert J. Culbertson, Sofia Benitez-Brady (Arizona State University); Barry J. Wilkens (LeRoy Eyring Center for Solid State Science at Arizona State University); Nicole Herbots (Arizona State University)

The surface energy of silica is correlated with topography and composition in micron thick films on polycarbonate visors for football, hockey, ski and scuba diving.

Use of visors can be limited by condensation that occurs in during athletic performance. Control of the hydro-affinity of the surface requires an understanding of hydrophobic/hydrophilic behavior as well as of condensation kinetics and surface contamination for up to several continuous hours

Combining Proton-Induced X-ray Emission (PIXE), Tapping Mode Atomic Force Microscopy (TMAFM) & the Sessile Drop Method with Contact Angle Analysis (CAA) using Young-Dupre Equation, yields insights into nucleation and ripening of water droplets. Real-time observation via optical microscopy of both reflected and transmitted light, PIXE, TMAFM and CAA with previous Rutherford Backscattering Spectrometry (RBS) results ca establish a model to predict surface energy and hydro-affinity of silicates, phospho-silicates and other compounds used for high impact resistance vision wear coatings. Ultimately, the goal is to control condensation on such coated polymers for applications in sport eyewear used in hockey, skiing, football and other contact sports, swimming goggles, and diving masks.

Surface characterization techniques in this research combine the 4.265 ± 0.035 MeV 12C(alpha, alpha)12C and the 3.05 ± 0.005 MeV 16O(alpha, alpha)16O MeV Oxygen Nuclear Resonance to increase light atoms detection with 2.8 MeV Hydrogen Elastic Recoil Detection for compositional analysis with depth profiling, and Tapping Mode Atomic Force Microscopy for surface topography. The water affinity of the solid surface is measured via contact angle analysis using the Sessile Drop method calibrated with standards such as OH(1x1)Si(100), 100 nm thermal oxides on Si(100), Si(100) amorphized by high dose Si ion implantation at 35-175 keV, alpha-quartz crystals, and the Young-Dupré equation to compute surface energy. The surface energy is then correlated with statistical analysis of Tapping Mode Atomic Force Microscopy topographs and PIXE/RBS analysis to predict and determine the mechanism and kinetics of water condensation. Polymer adsorption on these surfaces is used to alter the surface hydroaffinity and maintain clarity when condensation occurs by making it hydrophilic [1].

[1] US Patent pending "Molecular films for controlling hydrophobic, hydrophilic, optical, condensation and geometric properties of Si-based surfaces. Inventor(s): N. Herbots, J. D. Bradley, M. A. Hart, D. A. Sell, S. D. Whaley, Q. Bradley (filed: November 9, 2009)

AS-TuP-28 An Investigation of Primary Ion Choices in Depth Profiling Using Time-of-Flight Secondary Ion Mass Spectrometry
Zihua Zhu, Vaithiyalingam Shutthanandan (Pacific Northwest National Laboratory)

Depth profiling is one of the important applications of time-of-flight secondary ion mass spectrometry (ToF-SIMS). Dual beam depth profiling strategy is commonly used because the current of the primary ion beam is normally very weak (~10-12 A), and the second beam with high current (10-8-10-6 A) is introduced for sputtering. Recent years, a major development in ToF-SIMS field is application of cluster primary ions. It has been found that cluster primary ions can dramatically enhance signal intensity of molecular ions with a factor of 10-1000. So far, cluster primary ions have been introduced into commercial ToF-SIMS instruments for over five years. However, in presently available commercial ToF-SIMS instruments, the usable currents of cluster primary ion beams are considerably smaller than that of monatomic primary ion beams. More importantly, enhancements using cluster primary ions are not only material-dependent but also ion species-dependent. Therefore, large amounts of experimental data are needed to develop an understanding of how to choose an optimal primary ion for ToF-SIMS depth profiling.

In this work, we studied depth profiling of several representative systems: (1) Hydrogen depth profiling in silicon wafer, zinc oxide crystal and normal glass; (2) molecular depth profiling of a thin sucrose film on silicon substrate; (3) molecular depth profiling of Irganox “delta” layers prepared by NPL, United Kingdom . Six primary ion beams (25 keV Bi+, Bi3+, Bi5+, 50 keV Bi3++, 10 keV C60+ and 20 keV C60++) were compared. Our data show that enhancement of cluster primary ions for elemental species is limited (~1.5-4.0 times) if compared to that for molecular species (>>10 times). Considering the highest usable currents of difference primary ion species on presently available commercial ToF-SIMS instruments, we suggest that monatomic primary ion beams may be the best choice for elemental depth profiling, and cluster primary ion beams are better choices for molecular depth profiling.
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