Accurate RBS measurement of ion implant doses in silicon

We demonstrate very accurate ion implant dose measurements using Rutherford backscattering spectrometry (RBS) traceable to a certified reference material from IRMM, Geel and the Bundesanstalt für Materialforschung (BAM), Berlin. The measurements have an absolute accuracy of better than 1.4% and a precision of better than 1.25%. The certified standard sample is compared directly with recent absolute determinations of the energy loss of He in Si, and also with a sample calibrated against the Harwell Bi standard. We determine the dose in a series of three In implants and six As implants of various doses and energies. Some of the samples were amorphized to eliminate channelling effects. A double detector geometry was used, giving pairs of spectra with a common incident charge but where the solid angle and the electronic gain were determined for each detector channel independently. The statistical uncertainty is reduced to