Accelerator based mass spectrometry of semiconductor materials

We have investigated the possibility of using accelerator based mass spectrometry for the study of semiconductor materials, especially Si and GaAs. Several impurities have been examined, including B, Be, Si, Nb, Sb and Te. For most of these impurities, the count rates from high background levels in the ion source totally dominated the signals from the samples. For Nb, however, the background levels were quite low, and detection limits of approx.=0.1 parts-per-billion have been demonstrated. The results discussed here suggest that the technique is applicable to most impurity-substrate combinations, but the development of a clean ion source is necessary for routine use of this method. (orig.)