We present a Monte Carlo investigation of noise and velocity fluctuations in Si at 300 K under full degenerate conditions. The presence of the Pauli principle is found to strongly modify the shape of the correlation functions: at low electric fields, the time decay decreases due to the shortening of momentum relaxation time and the variance evidences nonparabolicity effects. At increasing electric fields, the correlation function exhibits a negative part that can be associated with ballistic carriers crossing the velocity space from negative to positive values of the Fermi velocity without scattering. A microscopic analysis in terms of diagonal and off‐diagonal contributions to the velocity correlation confirms this interpretation. ©1996 American Institute of Physics.