This thesis owes its existence to the help, support, and inspiration of many people. In the first place, I would like to express my sincere appreciation and gratitude to Prof. Siegfried Selberherr for his support and encouragement during the more than four years of this thesis's work. He has provided for an optimum working environment at the Institute for Microelectronics, where a lack of resources is something unimaginable due to his managerial skills and foresight. His uncompromising quest for excellence significantly shapes everyone at the institute. I am also indebted to Prof. Dietmar Dietrich, who agreed to serve on my examining committee on very short notice.
The discussions and cooperations with all of my colleagues have contributed substantially to this work: Christoph Pichler has been an inexhaustible source for discussions on all kind of TCAD aspects; Rudolf Strasser has put a lot of enthusiasm and energy in the development of the SIESTA framework; Michael Stockinger suggestions and comments helped to improve the usability of the optimization environment; Robert Mlekus has given advice in software engineering aspects; and to my room-mate Robert Klima for many interesting discussions, not only about microelectronics but also about other important things in life. I also extend my appreciation to all staff members of the Institute for Microelectronics for their assistance and support.
I am very grateful to Humbert Noll, Andreas Bauer, and Rainer Minixhofer from Austria Mikrosysteme International, Unterpremstätten, Austria, and the ``Christian Doppler Gesellschaft'', Vienna, Austria for supporting my studies.
I would also like to thank Peter Hopper, Philipp Lindorfer and Hannes Stippel from National Semiconductor Corporation, Santa Clara, California for their support during my summer-internship.
Finally, I owe special gratitude to my family for continuous and unconditional support of all my undertakings, scholastic and otherwise, and to my wife Rita for her patience, understanding and love.