Papers

AVS1996 Session AS-TuA: Standard Materials, Methods and Data: Honoring ASTM E42 20th Anniversary

Tuesday, October 15, 1996 2:00 PM in Room 105B

Tuesday Afternoon

Start	Invited?	Item
2:00 PM		AS-TuA-1 ASTM E-42 at Twenty Years -- Looking Back at Its Formation R. Koch (Armco Inc.) This AVS 43rd National Symposium marks the twentieth anniversary of the first meeting of ASTM Committee E-42 on Surface Analysis. At the 1976 AVS National Symposium in Chicago, ASTM Committee E-42 held an organizational meeting, elected officers, and established a subcommittee structure. This paper will discuss from an historical viewpoint the events leading up to the formation of Committee E-42 and also the accomplishments of its early years.
2:20 PM		AS-TuA-2 Standard Test Data for XPS J. Conny, C. Powell, L. Currie (National Institute of Standards & Technology) We have developed a prototype set of standard test data (STD) for x-ray photoelectron spectroscopy (XPS). The data were then evaluated by a number of analysts from industry, academia and government. STD are simulations of overlapping carbon 1s XPS spectra, and were designed to assess data analysis procedures for determining peak position and intensity. The STD consisted mainly of doublet spectra constructed from mathematical models of measured C1s spectra of polymers. Different pairs of the polymer spectra were combined in a factorial-type design to simulate binary polymer specimens exhibiting varying degrees of peak overlap, varying degrees of relative peak intensity, and varying levels of absolute peak intensities for the overall spectrum. Poisson noise was added in replicate to simulate multiple experimental measurements of the same specimen. In addition to doublet spectra, spectra of single C1s peaks were included in the set as the null condition.Participants in the evaluation study were asked to use their individual data analysis procedures to estimate peak position and intensity parameters, and to estimate uncertainties in these parameters. Participants had to choose whether one or two peaks were present, and which background correction, fitting function, and initial peak-fitting parameters to use. We will present summaries of the range of peak parameters reported, and we will discuss the types of operator choices used, overall impressions of the prototype STD and future directions for STD in surface spectroscopy.
2:40 PM		AS-TuA-3 Growth and Characterization of Aluminum Oxide Thin Films for Evaluation as Reference Materials S. Gaarenstroom (General Motors R&D Center) With the aid of aluminum oxide reference films, analytical techniques which previously provided only relative thickness information can now report absolute mass thickness measurements for aluminum oxide films. These new reference films were dense, nonporous, anodic aluminum oxide films grown by the method of Haas with a thickness range from 12 nm to 135 nm. Dimensional thickness measurements were made by transmission electron microscopy and spectroscopic ellipsometry. Absolute mass thickness measurements were made by electron probe microanalysis and energy-dispersive x-ray microanalysis. Relative thickness measurements were made by infrared spectroscopy, x-ray photoelectron spectroscopy depth profiling, and wavelength-dispersive x-ray fluorescence spectroscopy. Characterization measurements show the growth recipe (1.35 nm/V) predicts the dimensional thickness within 5-10% and the mass thickness within 10%. Numerous surface-processing procedures involving aluminum material, such as brazing, welding, wetting, bonding, stamping, and rolling, will benefit from improved measurements of oxide-layer thicknesses on aluminum or aluminum alloys.
3:00 PM		AS-TuA-4 Deteriorating Factors of Depth Resolution in AES Depth Profiling of Multilayered Systems K. Satori, Y. Haga, R. Minatoya, M. Aoki, K. Kajiwara (Sony Corporation, Japan) The effects of both the sputter-induced roughness and the escape depth on the depth resolution \Delta\z and on the interface position z\sub c\ (defined as the position of 50% intensity) were studied in AES depth profiling of a Ni/Cr multilayered system. First, the sputter-induced roughness was evaluated by atomic force microscopy (AFM). Secondly, both the depth resolution and the interface position were evaluated quantitatively using an error function fitting method of AES depth profiles. It is found from the AFM observation that the height distribution of sputter-induced roughness is approximated in a first order by a Gaussian distribution and is correlated with the resolution function which depends strongly on the sputter-induced roughness. Evidently the AFM observation is most useful to evaluate quantitatively the sputter-induced roughness. It is also found that the sputter-induced roughness is a dominant factor which determines the dependence of \Delta\z on the sputtered depth z under such a condition of Ar\super +\, 1 keV, 55deg. Strictly speaking, the real height distribution is, however, somewhat different from the Gaussian distribution. It is found from the computational simulation using the error function approximation fitting that an anomaly on z\sub c\ is discernible at the only Ni/Cr interface. It is supposed that the Ni enrichment occurs at the Ni/Cr interface due to the preferential sputtering. In addition, the experimental results in a similar way on an AlAs/GaAs superlattice will be presented and will be compared with those on the Ni/Cr multilayered system.
3:20 PM		AS-TuA-5 Surface Chemical Analysis - Comparing Data Between Laboratories M. Seah (National Physics Laboratory, United Kingdom) The technology and interpretation of surface analysis has developed continuously in the 28 years since the foundation of the basic methods of AES, XPS and SIMS. ASTM E-42 has been in the forefront of this development for much of the period and established many of the methodologies presently used for the pan-laboratory co-ordinations which are an essential ingredient in the development of today's analytical methods. One aspect of this approach will be illustrated by a new inter-laboratory study for static SIMS. The development of standards is designed to assist the general user so that particular problems have been thought through and methods refined properly. Thus, the analyst does not have to re-invent the wheel to achieve front-line results. Examples of some new and developing standard methods for XPS will be given. Standards also cover interfacing between different areas and of communication between those areas. Data formats and easy ways of exchanging and using data banks, which increase opportunity for analysts in treating data and in having access to extensive data sets, are all developing. These open significant new possibilities. Reference data, illustrated by measurements for AES, provide an essential link with other areas and basic theory. These aspects are all developing strongly throughout the world, encouraged as a result of the establishment of the International Standards Organization Committee, ISO TC/201 on surface chemical analysis, based on the initiatives of ASTM E-42
4:00 PM		AS-TuA-7 MAXMIND - A Data Storage and Evaluation Environment in Surface Analysis K. Brandl, H. Stoeri (Technische Universit\um a\t Wien, Austria) The problem of surface analytical data exchange for multi-method analysis has to be solved, in order to use data from a number of different surface analytical instruments (such as AES, SAM, XPS, SIMS, STM, AFM,...) in a synergistic manner. As only a standardised data exchange format can guarantee the independence of proprietary measurement systems without adaptation of existing software, the public domain software package MAXMIND(1) was developed based on HDF(2). A first key feature of MAXMIND is the strict separation of the software design and the development of data dictionaries (sets of parameters for various methods), thus data dictionaries can be modified without recompiling the software. The data dictionaries include in the present version of MAXMIND are in the case of AES and XPS based on the work by M.P. Seah et.al. and C.J. Powell et.al.. Dictionaries for other methods have been set up by the authors and are to be considered preliminary. Beside a GUI based on the X11 interface a second key feature are interfaces from MAXMIND to MATLAB and KHOROS, which both are well known data analysis environments in the surface analysis and image processing community. Using one of these interfaces a combination of either MATLAB or KHOROS in conjunction with MAXMIND forms an integrated data storage and evaluation environment. A first version of the MAXMIND software including all major components will be available at the time of the conference via WWW at URL 'http://www.iap.tuwien.ac.at/www/maxmind/'. (1) Management And Exchange of Method Independent Data (2) Hierarchical Data Format (work supported by Austrian Fonds zur Foerderung der wissenschaftlichen Forschung, project no. S6201 and Digital Equipment Corporation, EERP project AU033).