The invention relates to a simulation and/or layout process for vertical power transistors as DMOS or IGBT with variable channel width and variable gate drain capacity which can be drawn and/or designed by the designer with the respectively desired parameters of channel width and gate drain capacity and the parameters of volume resistance and circuit speed, which are correlated therewith, and whose electrical parameters can be described as a function of the geometrical gate electrode design. Here, both discrete and integrated vertical transistors may be concerned.