The quadrupole mass analyzer for solids (QMAS) is ideally suited for multielement analysis because of the rapid scanning capabilities of its quadrupole mass filter, the high sensitivity inherent in the secondary ion mass spectroscopy (SIMS) technique, and an instrumental configuration which produces abundance sensitivities in excess of 10⁵ to 1. These capabilities allow the elemental composition of solid specimens to be readily measured and permit the detection of contaminants and dopants on the surface as well as in the bulk of a specimen to be determined. A typical mass survey of a silicon specimen is shown and some of its features are discussed. Because of the correlation between the time of sputtering and the depth eroded into a specimen, multiple element in-depth profiles are also readily measured with QMAS. In-depth distributions of boron and phosphorus, both implanted and diffused into silicon, have been determined and are discussed. The effects of different specimen treatment histories are found to be reflected in the depth profiles obtained.

In addition to depth profiling, the instrument has been used successfully for isotope ratioing. Work done with the lead isotopes indicates that the accuracy of the measured ratios is limited only by counting statistics. The accuracy of these analyses verifies that the instrument can be used routinely to analyze insulators. These studies also illustrate that spectral ion interferences can often be successfully treated by peak stripping techniques. In the same study, the analytical problems associated with possible mass discrimination and the ability to obtain quantitative elemental analyses have been investigated and the results compared with the ion microprobe mass analyzer (IMMA).