Hot-carrier constraints on transient transport in very small semiconductor devices

The consequences of changes that the short-time scales have on the transport of carriers in small semiconductor devices are examined. Consideration is given to the effect of the nonnegligible collision duration and the concomitant intracollisional field effect, effects on the transport equation with emphasis on the transient dynamic response, and the concepts of diffusion and the velocity autocorrelation function. It is found that the autocorrelation function initially relaxes exponentially, goes negative and displays a local minimum, and then relaxes to zero at a slower rate due to energy relaxation. This behavior leads to enhanced diffusion and noise on the short-time scale