Previous work in this field was essentially based on analytical investigations, circuit simulations with conventional compact models, and experimental work. Despite the importance of such work these approaches suffer from a number of disadvantages: analytical investigations are limited to simplified special cases, circuit simulations based on conventional compact models experience accuracy problems at low voltages and short channel lengths, and experimental work is again limited to the investigation of particular cases built with available technologies
Although present Technology Computer Aided Design (TCAD) software and physical models lack the predictive strength which is common, e.g., to circuit simulation under standard conditions TCAD has become an dispensable part of VLSI technology development, where it is being used for explorative device studies and for technology fine-tuning and optimization.
TCAD has been of fundamental importance for this work, and for some tasks - most notably for the implementation of a VLSI performance performance metric and for developing a new device model for circuit simulation - TCAD methods had to be refined or newly developed. Yet, there is no special TCAD chapter contained in this thesis because - apart from the programming work which was ULP specific - TCAD software could be used like other standard tools in fairly routinely manner.