We studied accurate depth profiling for ultra-shallow implants using backside SIMS. In the case of measuring ultra-shallow profiles, the effects of surface transient and knock-on are not negligible. Therefore, we applied backside SIMS to analyze ultra-shallow doping to exclude these effects. Comparing the SIMS profiles of surface-side and those of backside, backside profiles show a sharper ion implantation tail than surface-side profiles. Furthermore, backside SIMS profiles show almost no dependence on primary ion energy. This indicates that backside SIMS provides sharp B profiles suitable for analyzing ultra-shallow implants, using higher primary ion energy in comparison with implantation energy. The backside SIMS technique has a good potential to be used for next generation devices. (C) 2002 Elsevier Science B.V. All rights reserved.