Numerical modeling of fluctuation phenomena in semiconductor devices

Abstract

A method enabling numerical modeling of fluctuation phenomena in semiconductor devices is presented. The method is based on the assumption that fluctuations of generation–recombination processes and carrier mobility result in the fluctuations of carrier and ionized impurity concentrations. These, in turn, may be expressed by the fluctuations of the electrical potential and quasi-Fermi levels. Fluctuations of the electrical potential and quasi-Fermi-levels were calculated by solving the set of “transport equations for fluctuations” in which the fluctuations of generation–recombination processes (both thermal and optical) and fluctuations of mobility play roles of random source terms. The method enables the calculation of fluctuations of all physical quantities enclosed in a set of transport equations. The spatial distribution of the fluctuations of the electrical potential, electron concentration, and noise current density is shown. The noise spectrum in selected, cooled, long-wavelength HgCdTe photoresistors is calculated and the contribution of different noise sources is determined. Theoretical results are compared with experimental data.