Even the newest and most sophisticated measurement techniques have only limited means of determining the distribution of physical quantities inside a semiconductor device. Often the only means of looking into the transistor and analyzing the distribution of the physical quantities is by process or device simulation [27]. With inverse modeling, parametrized dopant profiles are used for the simulation of, usually, the electrical device characteristics which are compared to measured data. This is carried out in an optimization loop where the result is the approximated doping profile of the analyzed device.