Today, grid generators are complex and sophisticated stand-alone tools. Grid generation is no longer performed via control by the device simulator as a preprocessing step but rather as a separate step before simulation.
Grids have heavy impact on results obtained by device simulation. The demands on grids rise even for three-dimensional device simulation and the generation of a proper grid is a challenging task. Some requirements have been already depicted in Section 2.2.3. However, a grid used for device simulation must fulfill some criterions which are addressed in this section.