AVS 52nd International Symposium
    Applied Surface Science Wednesday Sessions
       Session AS-WeM

Paper AS-WeM6
Complete Analysis of ToF-SIMS Spectral Images in a Research and Development Analytical Laboratory

Wednesday, November 2, 2005, 10:00 am, Room 206

Session: Essential Tools for Surface Analysis
Presenter: V. Smentkowski, General Electric Global Research Center
Authors: V. Smentkowski, General Electric Global Research Center
M. Keenan, Sandia National Laboratories
J.A. Ohlhausen, Sandia National Laboratories
P.G. Kotula, Sandia National Laboratories
Correspondent: Click to Email
Time of flight secondary ion mass spectrometry (ToF-SIMS) spectral image raw data files contain a wealth of information since an entire mass spectrum is saved at each pixel in an ion image. Currently, few tools are available to assist the analyst in visualizing the entire raw data set and as a result, most of the measured data are never analyzed. Typically, the ToF-SIMS analyst manually selects a few species to monitor based upon input from the customer, knowledge of results obtained from similar past analysis, high peak intensity and/or unusual species detected in the spectrum. Manual analysis is complicated by the fact that little is known about real-life samples prior to analysis. The analyst is expected to perform rapid, cost effective, analysis and provide a complete description of the sample. Automated, non-biased, multivariate statistical analysis (MVSA) techniques are useful for converting the massive amount of data into a smaller number of components that are needed to fully describe the ToF-SIMS measurement. We are using AXSIA to perform MVSA on ToF-SIMS raw data files. The advantages of AXSIA include: the ability to select the mass range of interest, the ability to bin the mass spectra from 0.001amu to 1amu, optimal scaling of the data to account for Poisson counting statistics, and the generation of intuitive results. Examples will be selected to demonstrate these advantages. We will also demonstrate that positive ion and negative ion raw data files collected on the same region of a sample can be concatenated. MVSA analysis of the concatenated data provides a complete description of the sample. The analytical insight provided by concatenated MVSA analysis would be difficult, if not impossible, to obtain via other routes. Sandia National Laboratories is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.