CURRENT AND NUMBER FLUCTUATIONS IN SUBMICRON N+NN+ STRUCTURES

We present a detailed analysis of current and number fluctuations in submicron n+nn+Si structures at different bias voltages and lengths of the active region. The calculation is carried out by coupling self-consistently a one-dimensional Poisson solver with a three-dimensional Ensemble Monte Carlo simulator. The coupling between fluctuations in carrier velocity and in the self-consistent field is found to be responsible for a negative part (a minimum) in the autocorrelation function of current fluctuations at equilibrium. The fluctuations of the carrier number in different slices and in the whole structure are influenced by space-charge effects and by the inhomogeneity of the structure. They are found to be a sensitive probe for characterizing different contact models. With increasing applied voltage the coupling between velocity and electric-field fluctuations weakens due to a less effective screening.