We studied accurate depth profiling for ultrashallow implants using backside secondary ion mass spectrometry (SIMS). For measuring ultrashallow dopant profiles such as 200 eV B implantation profiles, the effects of surface transient and atomic mixing are not negligible. We applied backside SIMS to analyze ultrashallow doping in order to exclude these effects. Comparing the SIMS profiles of surface side and those of backside, backside SIMS profiles showed a shallower ion implantation tail than surface-side SIMS profiles. Furthermore, backside SIMS profiles showed almost no dependence on primary ion energy. This indicates that backside SIMS provides sharp B profiles suitable for analyzing ultrashallow implants, even in the case where higher primary ion energy is used in comparison with implantation energy. The backside SIMS technique has a good potential to be used for the development of next-generation devices. (C) 2003 American Vacuum Society.