The shave-off depth profiling is one of the most powerful techniques to obtain accurate elemental depth distributions from small particles and samples with rough surfaces. In order to clarify the factors determining the depth resolution and to estimate the ultimate depth resolution by the shave-off depth profiling, simulations of shave-off process and experiments on a model multilayer sample were performed. The simulation revealed that the key factors to realize the best depth resolution were alignment of the primary beam and the sample, and the shave-off speed. The simulation showed the best depth resolution of 3nm with precise alignment of the primary beam and the sample under the current experimental setup. From the measured depth profile of a TiN thin layer, the depth resolution of 21nm was determined. When the state-of-the-art focused ion beam is used as the primary beam, the practical depth resolution of 1.4nm is expected for the analysis of the sample with 1μm2 cross section.
