Distortion of SIMS profiles due to ion beam mixing

Secondary ion mass spectroscopy (SIMS) is one of the most important tools in analyzing dopant profiles in silicon technology. During SIMS analysis, target atoms are sputtered by an ion beam so that, by mass separation, depth profiles of impurities are obtained. When analyzing shallow dopant distributions, the profile shape can be distorted significantly by ion-beam mixing induced by the sputtering process. In this work, the effects of ion beam mixing on dopant profiles are analyzed experimentally and theoretically via delta-response functions, the SIMS signals of delta-doped layers. Methods for the reconstruction of true dopant profiles are discussed and applied to profiles of arsenic and antimony implanted at low energies.