Nonexponential generation-recombination dynamics in doped semiconductors as a possible source of high-frequency 1/f noise

We present a theoretical study of generation-recombination processes from shallow impurities which includes self-consistently the contribution of the impurity excited levels. Making use of an original Monte Carlo simulation which accounts for both the kinetic energy of the carrier and its potential energy near the impurity, we have solved the semiclassical Boltzmann equation to investigate the dynamics of generation-recombination processes on a kinetic level. Calculations performed for the case of p-type Si clearly evidence a nonexponential distribution of the microscopic times spent by the carriers in the impurity centers and in the conducting band. This in turn leads to the impossibility of a rigorous definition of a carrier lifetime and therefore to a possible source of high-frequency 1/f noise. The theory is found to compare favorably with available experiments.