The use of oxygen flooding and an amorphous Si capping for secondary ion mass spectrometry (SIMS) depth profiling of ultralow-energy implants is discussed in terms of the accuracy of the depth and concentration scale. Further, the advantages of a lower primary ion energy and the simultaneous mass registration on a time-of-flight-SIMS with dual beam mode is illustrated. Finally, the effects of ultrahigh top concentrations on the tail of implantation profiles is investigated.