For 1 um Si MOSFETs, the spatial transient effect can make up to 20% modification of the local mobility. This effect is certainly larger in submicron devices. In this computational project, we will investigate this effect by both analytical techniques as well as Monte Carlo simulations on the San Diego Cray XMP. The goal is to understand the transport physics at small distances involved in submicron devices and to obtain a mobility formula, simple and accurate, to use in device simulators. The major computational technique will be Monte Carlo procedures. This is an expedited award for novel research, for which no funds have been granted. The PI has been granted 50 service units at the NSF Supercomputer Center at San Diego.