Reduction of matrix effects in TOF-SIMS analysis by metal-assisted SIMS (MetA-SIMS)

Abstract

We investigated reduction of the matrix effect in time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis by the deposition of a small amount of metal on the sample surfaces (metal-assisted SIMS or MetA-SIMS). The metal used was silver, and the substrates used were silicon wafers as electroconductive substrates and polypropylene (PP) plates as nonelectroconductive substrates. Irganox 1010 and silicone oil on these substrates were analyzed by TOF-SIMS before and after silver deposition. Before silver deposition, the secondary ion yields from the substances on the silicon wafer and PP plate were quite different due to the matrix effect from each substrate. After silver deposition, however, both ion yields were enhanced, particularly the sample on the PP plate, and little difference was seen between the two substrates. It was therefore found that the deposition of a small amount of metal on the sample surface is useful for reduction of the matrix effect. By reducing the matrix effect using this technique, it is possible to evaluate from the ion intensities the order of magnitude of the quantities of organic materials on different substrates. In addition, this reduction technique has clear utility for the imaging of organic materials on nonuniform substrates such as metals and polymers. MetA-SIMS is thus a useful analysis tool for solving problems with real-world samples. Copyright © 2005 John Wiley & Sons, Ltd.