Analytical Study Of Drift Velocity In P-Type Silicon Nanowires

摘要

An analytical model that captures the essence of physical processes in a p- type silicon nanowire transistor is presented. The model covers seamlessly the whole range of transport from drift-diffusion to ballistic. The mobility and saturation velocity are the two important parameters that control the charge transport in a MOSFET channel. It is shown that the high mobility does not always lead to higher carrier velocity. The ultimate drift velocity due to the high electric-field streaming are based on the asymmetrical distribution function that converts randomness in zero-field to streamlined one in a very high electric field. The limited drift velocity is found to be appropriate thermal velocity for a non-degenerately doped sample of silicon, increasing with the temperature, but independent of carrier concentration. However, the limited drift velocity is the Fermi velocity for a degenerately doped silicon nanowire, increasing with carrier concentration but independent of the temperature.