A graphical study of the current distribution in short-channel IGFETS

Abstract

NUMERICAL SOLUTIONS of the Poisson's and continuity equations have been employed in a graphical study of a practical short-channel enhancement mode IGFET structure; Figure 1. The results are summarized here in a primarily tutorial paper, with emphasis on quantitative graphical display of the current, density, field, and potential distributions characteristic of the various qualitatively well understood IGFET effects; e.g. punch-through, pinch-off, sub-threshold conduction, etc. Points of novelty in the work reported lie in the method of solving the PDE (partial differential equations), and the model used to quantify the effects of scatter limitation and surface reduction of the electron mobility. The computed solutions have been compared to experiment (Figure 2), and the electron mobility model is illustrated for a typical bias situation in Figure 3.