Limitations of local models for semiconductor devices

The effects arising in one-dimensional structure of BARITT diode have been researched for nonsteady – state electron transport conditions. The investigation has been carried out by numerical model using equation of energy concervation which take into account the energy relazation of electron gas. Limitations of local models for $\mathrm{Si}$ and $\mathrm{Ga}\mathrm{As}$ are obrained. It has been shown that limits of application of local drift-diffusion models for GaAs are the characteristic length 0.5 micrometer and time scale 1.25 pS, for $\mathrm{Si}$ 0.05 micrometer and the same time scale.