As implant energies get lower and lower, significant errors can be present in junction depth measurements in secondary ion mass spectrometry (SIMS) ultrashallow depth profiling. Primary beam ion mixing is one of the main sources of errors leading to overestimation of junction depths in SIMS measurements. In this article, we systematically study the correlations between the implant profile trailing edge, junction depth and primary ion beam energy for low energy boron and arsenic implants. Using a mathematical deconvolution model proposed by Yang and Odom [Mater. Res. Soc. Symp. Proc. 669, J4.16.1 (2001)], we are able to estimate the error of the junction depth and consistently improve the accuracy of junction depth measurements using SIMS. (c) 2006 American Vacuum Society.