Retrospective sputter depth profiling using 3D mass spectral imaging.

A molecular multilayer stack composed of alternating Langmuir-Blodgett films was analyzed by ToF-SIMS imaging in combination with intermediate sputter erosion using a focused C cluster ion beam. From the resulting dataset, depth profiles of any desired lateral portion of the analyzed field-of-view can be extracted in retrospect, allowing the influence of the gating area on the apparent depth resolution to be assessed. In a similar way, the observed degradation of depth resolution with increasing depth of the analyzed interface can be analyzed in order to determine the 'intrinsic' depth resolution of the method.