The finite difference method requires an orthographic grid. In the two-dimensional case the
grid points are located at horizontal and vertical lines. The points must provide a good
resolution of the regions of the device where a strong variation of the quantities is
expected. Fig. 3.1 shows an example of such a grid. The grid lines are more dense
in the regions of strong variation of the carrier concentration, like the channel and the
junctions of the source and drain doping.
Schematic representation of an orthogonal mesh discretizing the active region of a
M. Gritsch: Numerical Modeling of Silicon-on-Insulator MOSFETs PDF