AVS 46th International Symposium
    Applied Surface Science Division Tuesday Sessions
       Session AS-TuP

Paper AS-TuP8
Observing Damage Produced during XPS Measurements

Tuesday, October 26, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: M.H. Engelhard, Pacific Northwest National Laboratory
Authors: M.H. Engelhard, Pacific Northwest National Laboratory
D.R. Baer, Pacific Northwest National Laboratory
G.C. Dunham, Pacific Northwest National Laboratory
Correspondent: Click to Email
An increasing amount of studies in our laboratory involve analysis of polymers, self assembled monolayers (SAMS) with different terminations, insulators and other materials for which some properties of the specimens degrade with time during x-ray exposure. When damage is observed, a series of parameter tests are conducted to determine the conditions and time for which reliable data can be collected. In this paper we will report measurements made on SAMS with CH@sub 3@, OH and COOH, as well as some test coupons of PCEMA, PTFE and PVC. Most of these measurements were made on a Physical Electronics Quantum 2000 for which a variety of different x-ray flux densities can be arranged. In addition, the beam can be moved around to examine the regions over which damage occurs. Measurements for COOH terminated SAM show a damage production directly related to the flux per unit area. These, and other results, suggest that damage on many materials is not simply due to specimen heating. However, tests on PCEMA show damage to occur outside the region that was exposed to the x-ray beam. These tests will be described along with a new series of experiments being undertaken to determine if specimen cooling provides a way to decrease specimen damage. This work was conducted in the W. R. Wiley Environmental Molecular Sciences Laboratory, a national scientific user facilty sponsored by the U. S. Department of Energy's Office of Biological and Environmental Research.