Paper AS-TuP11
Short and Long-term Sputter Rate Constancy Measurements

Tuesday, October 16, 2007, 6:00 pm, Room 4C

The use of ion sputtering to obtain relative and absolute depth information about surface layers and films is a common application of Auger and photoelectron spectroscopy. Accurate information about sputter rates for different materials and reproducible information for similar systems requires that the conditions of operation of an ion gun be fairly well characterized and the parameters needed to obtain reproducible sputter conditions be understood. Unfortunately, most of us do not have a good sense of how stable and reproducible our actual sputter rates are. We have undertaken a study to determine the constancy of sputtering over short and long periods of times as these determine how long of a warm-up time is necessary prior to conducting sputter rate profiles, how much variability occurs during the course of an experiment, and how often one must perform sputter rate calibrations. We have three surface analysis systems, either manually or digitally controlled, in which we are conducting these constancy measurements. We have found that for one digitally controlled system, sputter rate are fairly constant over a period of a year. In the short term, sputter rates are constant following a short warm-up time. For a manually controlled system, the sputter rate is constant over a period of days provided the settings do not change over that period of time. Determination of the long-term variability of a manually controlled system for argon ion sputtering at fixed energies is part of an on-going effort. These sputter rate constancy measurements are being conducted in a Phi Quantum 2000 XPS system, a Phi 680 Auger Nanoprobe system, and a Kratos Axis 165 multitechnique system. We will provide comparisons of sputter rate constancy for these systems over the short and long-term.