The potentialities of the direct bombardment mode of secondary neutral mass spectrometry (SNMS) for depth profile analysis are discussed. In particular the achievement of extremely high depth resolution by using ion bombarding energies on the order of only 102 eV is emphasized. Low energy SNMS is applied for depth profiling of implantation profiles of As and P in Si. The range parameters obtained from the measured profiles are compared with theoretical values. By means of the high depth resolution, detailed structures in the unannealed implantation profiles are quantitatively determined and partially explained by the presence of residual surface oxides.