CHARACTERIZATION OF STRUCTURE DOPANT BEHAVIOR BY ELECTRON-MICROSCOPY

Transmission electron microscopy analyses that result in a quantitativ e 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-depend ent material features, which impact on structure/dopant behavior for s ilicon-based material systems. In order to illustrate the situation, t he determination of the vertical and lateral donor distribution is add ressed, and the case of diffusion into a [100] silicon substrate from a patterned structure of arsenic implanted and rapid thermally anneale d polysilicon is discussed. The so-called chemical etching technique i s used to delineate arsenic by local variations in the crystal thickne ss. It is demonstrated that a two-dimensional isoconcentration contour that maps the arsenic distribution can be quantitatively characterize d at the nanometer scale from cross-sectional transmission electron mi croscopy data, which are recorded under high-resolution imaging condit ions. 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.