FIRST AND FOREMOST I want to thank my superviser Prof. SIEGFRIED SELBERHERR that he gave me the chance to join his research group and to take a doctoral program at the Institute for Microelectronics. I am very grateful that he guided and supported me and my scientific work through all the years. Further, I am thankful that Prof. SELBERHERR gave me the necessary time and freedom to finish all my scientific activities successfully.
I am also indebted to Prof. ERASMUS LANGER, the head of the Institute for Microelectronics. Prof. LANGER has always been a very cooperative head and he has done a very good adiminstration. He let me take part in international research projects which was an important experience for me. I also thank Prof. MICHIEL VELLEKOOP that he agreed to participate in the examining committee.
My thanks also go to Dr. HAJDIN CERIC and Dr. ANDREAS HÖSSINGER who bootstrapped me at the Institute. With HAJDIN I had a lot of valuable discussions during all the years and he has been a pool of constructive ideas and elaborated suggestions. Furthermore, he proofread this thesis and gave good comments.
Since joining the Instiute Dr. ALIREZA SHEIKHOLESLAMI has been my room mate. He has been a very pleasant and very helpful colleague. With him I had a lot of interesting discussions, lots of funny moments, and so many lunches at Mensa. He also proofread this thesis.
I would also like to thank STEFAN HOLZER for his cooperative nature, especially in case of the electro-thermal simulations.
In case of several computer system or network problems Dr. JOHANN CERVENKA was always willing and able to help. Furthermore, here I would like to say thank you to all my colleagues throughout my time at the Institute, because all of them were always very friendly and helpful. There was always a very pleasant atmosphere.
Finally I thank my parents for their never ending support.