One of the founders of modern Technology Computer Aided Design (TCAD), Siegfried Selberherr has provided modeling and software development tools invaluable to the continued miniaturization of semiconductor devices. TCAD involves the use of computer simulation to develop and optimize semiconductor processing technologies. Selberherr developed MINIMOS for two-dimensional predictive simulation of the electrical characteristics of miniaturized devices to understand and control the short-channel effects and doping profiles encountered as device sizes shrink. MINIMOS was later enhanced for three-dimensional simulation to address energy transport and interface physics. He also created the ZOMBIE and PROMIS simulators, which incorporated mesh generation and programming interfaces. Selberherr then developed the Vienna Integrated System for TCAD Applications (VISTA) to combine both process and device simulation tools in a common framework. An IEEE Fellow, Selberherr is a professor with the Institute for Microelectronics at the Technische Universität Wien, Vienna, Austria.