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 mum design rules and below.