I want to express my gratitude to all people who supported my work for this thesis. Most important of course Prof. Dr. Siegfried Selberherr who continuously encouraged and supported this work and who provided the superb environment at the Institute for Microelectronics. He also made financial support available which enabled the visit of several interesting conferences in Europe and the USA.
Many colleagues at the Institute supported my work for this thesis. Claus Fischer and Thomas Simlinger developed the concept and implemented the first version of MINIMOS-NT and thereby created the basis for this thesis. Tibor Grasser and Martin Knaipp were my closest coworkers in extending, improving and using MINIMOS-NT. The frequent discussions with them considerably enhanced my understanding of semiconductor physics and device modeling. Richard Plasun, Gerhard Schrom, and Rudolf Strasser always were able to help and to solve problems with running MINIMOS-NT in a TCAD framework and the coupling to other simulators and optimizers.
Special mentioning is due to Robert Mlekus with whom I not only shared much time during school and the study of electrical engineering but also during swimming, mountain biking, and a trip to New Zealand.
When working in such a heterogeneous computer environment as the Institute for Microelectronics the work of system administrators is especially difficult and challenging. Most of the time they were able to provide an environment in which it was a pleasure to work. This became especially apparent when visiting other institutions where system administrators were not as ambitious.
Thanks are due to all proofreaders for their laborious work of reading various versions of this thesis, pointing out flaws and errors, and suggesting improvements. It was quite dismaying to see how many errors I did not notice myself and which were detected by the numerous proofreaders.
I would like to thank Llanda Richardson, Johann Nittmann, and Norbert Seifert for the possibility to visit Digital Semiconductor and to work with them on the AVC project. Even though this visit took place in a time of major changes at Digital Semiconductor the work was very interesting and the cooperation was quite successful.
The work on this thesis was supported by the ``Christian Doppler Forschungsgesellschaft'' and Austria Mikro Systeme.
Finally I want to thank my parents for their continuous support during all the years of my study. This enabled me to concentrate on the work for this thesis.