Transmission electron microscopy analyses that result in a quantitative characterization of structure/dopant behavior at the nanometer scale are the focus of this research activity. Of particular concern is the quantitative characterization of sequential changes in process‐dependent material features, which impact on structure/dopant behavior for silicon‐based material systems. In order to illustrate the situation, the determination of the vertical and lateral donor distribution is addressed, and the case of diffusion into a 〈100〉 silicon substrate from a patterned structure of arsenic implanted and rapid thermally annealed polysilicon is discussed. The so‐called chemical etching technique is used to delineate arsenic by local variations in the crystal thickness. It is demonstrated that a two‐dimensional isoconcentration contour that maps the arsenic distribution can be quantitatively characterized at the nanometer scale from cross‐sectional transmission electron microscopy data, which are recorded under high‐resolution imaging conditions. The evaluation of microstructural features is briefly considered, and it is concluded that the structure/dopant characterizations that are reviewed in this paper define necessary input parameters for two‐dimensional process and device simulation at 0.25 μm design rules and below.