Ballistic/quasi-ballistic transport in nanoscale transistor

The current voltage characteristics of the silicon ballisticMOSFETs are introduced and discussed. They arederived by considering the current capacity through the bottleneck point in the channel, and they providea simple measure of the performance limit. The performance of experimental nanoscale bulk MOSFETsare compared with the ideal ballistic limit. It was shown that the performance degradation due to carrierscattering amounts to several to several tens percent in recent nanoscale MOSFETs. Quasi-ballistictransport in MOSFETs was also analyzed by a simple approach based on the transmission viewpoint.Channel-length reduction was found to yield consistent improvement of the ballisticity. Considerableperformance degradation, however, was still found to persist even in 10-nm MOSFETs. The role of eachcarrier scattering mechanism is analyzed. It is shown that elastic scattering degrades the performance,but the inelastic energy relaxation improves the performance of the MOSFET