Dose calibration for through-oxide doping distributions from time-dependent secondary-ion-mass-spectrometry depth profiles with only one sensitivity factor

A simple method is described for calibrating the dose of impurity depth pro files in Si, SiO2, and SiO2 on Si by secondary ion mass spectrometry (SIMS) . Use is made of the fact that, with normally incident O-2(+) beams, the io nization probabilities of impurity and matrix secondary ions as well as the partial Si sputtering yields are the same for Si and SiO2. This allows dos e calibration against a reference sample to be achieved for any sequence of layers of the two materials and without depth calibration. SIMS profiles o f 5 keV B-11 equal-dose implants in Si, SiO2, and a thin layer of SiO2 on S i show that the concept is valid to +/-1% or better. Differences in the ref lection coefficient of B-11 from the different targets could be identified clearly. (C) 1999 American Institute of Physics. [S0003-6951(99)00326-5].