Acknowledgment

First and foremost I have to thank the people from the Institut f"ur Mikroelektronik. Not only for conveying the experience and knowledge to solve my work, also for forming new friendships. Foremost, my gratitude goes to Prof. Siegfried Selberherr who directed me to my thesis. With the required strength he showed me the way to finish my work. Thanks to Ewald, Manfred, and Frau Winkler for the excellent infrastructure.

I am very grateful to the Christian Doppler Forschungsgesellschaft, Wien, Austria as well as our industrial partners, Austriamicrosystems AG, Unterpremst"atten, Austria and Infineon Technologies Villach AG, Villach, Austria, for funding my studies. Beyond the context of this partnership, it was possible to build up a friendly working atmosphere. Thank also goes to Prof. Tibor Grasser who led me during parts of the work. Thanks for the guidance concerning the concept of my thesis. Thanks to all those who spent a lot of time with proofreading. Especially I want to thank Prof. Herbert Haas for the inspiring advice, which helped to improve the mathematical quality of the work.

During my work, I found a lot of friends at the institute. Primary thanks to my former room colleagues, Saba, Highlander, Andy, Wolfi, and Robert. We spent nice times -- not mandatorily at the institute. Thanks to the vi- and scriptking, adminking, networktestking, and mathking, for the inspiring high-level talks, problem solutions, mathematical discussions, nightly sessions, and culinary support. Naturally, also to all the colleagues I made friends with.

Special regards to all my friends, who watched me many years studying. And last but not least I want to thank my parents, my brother, and my relatives for supporting me during the whole time of my long-lasting education.

As a final remark to all my friends who are still studying or preparing a final work, good luck

and someday, it is finished.

Different Grids in the Silicon Segment of a Device Structure.