The decreasing feature size and increasing complexity of microelectronic materials presents a continuing challenge to TEM applications. Accurate mapping of structure and chemistry is required on the nano and atomic scales. Samples must be prepared that are representative and free of both artifacts and contamination. Once prepared, analysis by tomography allows visualization of the third dimension following image reconstruction. ADF STEM extends image resolution to the atomic scale, and may be combined with PEELS on the nanoscale. Dopant concentrations can be determined directly, based on differences in atomic number (or Z) image contrast. The behavior of p-n junctions can be studied in situ, using a novel combination of holography and electron beam induced current (EBIC).