A physical short-channel model for the thin-film SOI MOSFET applicable to device and circuit CAD

摘要

A charge-based large-signal transient model for the enhancement-mode thin-film SOI MOSFET in strong inversion, suitable for circuit simulators such as SPICE, is presented. The model physically accounts for the predominant short-channel effects in MOSFET's (namely threshold-voltage reduction, drain-induced conductivity enhancement, velocity saturation with mobility degradation, and channel-length modulation) as influenced by the unique features of thin SOI devices (i.e. the presence of an additional back gate and the possibility of a floating film body). It includes a description of generation current due to (weak) impact ionization, which can have a far greater influence on SOI (as compared to bulk) MOSFET's due to the associated charging of the floating body. Measurements on devices of varied geometry show good agreement with model predictions. The model is implemented in SPICE2, to be used for circuit and device CAD, and TECAP, for automated parameter extraction.