Hot-carrier fluctuations from ballistic to diffusive regime in submicron semiconductor structures

We present a theoretical analysis of number and current fluctuations in homogeneous n-Si resistors of submicron dimensions at increasing electric field strengths. To this purpose, we calculate the corresponding correlation functions. In the ballistic regime a simple scaling relationship of the transit time accounting for carrier heating is found to hold over the whole range of fields considered. In the diffusive regime different time scales associated with diffusion, drift and dielectric relaxation are found to characterize the behaviour of number fluctuations.