Nanoscale Device Modeling

Modeling of nanoscale devices is currently acquiring growing importance and is reaching maturity, in the sense that quantitative predictive capabilities have been achieved. In particular, modeling has become instrumental in the design of new devices, in the interpretation of experimental results and in the evaluation of new device proposals. In particular, this latter issue, the evaluation of new device proposals, has become extremely relevant in the last few years, after realizing that very significant research efforts have been spent into the development of technologies whose intrinsic weaknesses could have been detected from the very beginning, if realistic models had been considered, instead of very simple, idealized models, not including real-life nonidealities, such as fabrication tolerances, external interferences, asymmetries. It is at the same time apparent that a wide range of simulation tools is needed, at different levels of approximation: realistic models are required for single devices, in order to verify their operability in a variety of conditions and in the presence of imperfections. Higher-level, more approximate models must instead be developed to investigate circuits including from a few to millions or billions of devices: due to computational constraints, detailed models cannot treat more than a few devices at a time,therefore a hierarchy of simulation tools must be created, ranging from atomistic approaches to logic level simulations.