Semiconductor noise

A corpuscular-collective model of noise generated by the Shockley-Read-Hall (SRH) defect centers is proposed for the semiconductors. The interactions of the single-defect centers with the charge carriers both of the conduction and valence energy bands, with their currents and with generation-recombination (GR) current are taken into account. With regard to the unipolar conduction media and devices, such interactions make the analysis and its results much more complex. By starting from the SRH theory, we first determine the average occupation factor and GR current of the single multiple-energy-level defect and the relevant shot noise associated to the GR transitions. Then, again according to such a corpuscular approach, by taking into account the fluctuations of the quasi-Fermi-levels and of the electric potential, we compute the relaxation time and the Langevin equation of the single defect and the modulation which its charge fluctuations induce in the electron, hole, and GR currents. Finally the coupling problem between the defect and the currents of the device terminals is solved, by means of collective approach, by defining proper coupling coefficients between such output currents and the currents and charge injected into the defect itself from the conduction and valence bands. Then the relationships between such coefficients, for any shape and terminal number of the device, are computed in a general form by means of the transport, continuity, and Poisson equations and of a new method which allows us to evaluate the three- and two-dimensional effects of a single defect through a one-dimensional approach. The new model should be able to account for the thermal, shot, flicker, burst, and GR noises of the semiconductor devices, for any bias condition and for any defect number and allocation in the neutral and space-charge regions.