Possible mechanisms for 1/f noise in chalcogenide glasses: A theoretical description

We present a comprehensive theoretical study of 1/f noise in chalcogenide glasses aimed at applications to the developing technology of phase change memory. Our consideration is based on a body of formerly established facts about the atomic and electronic excitations specific to the chalcogenide glasses, which have not been considered in recent work; we give a brief survey of the relevant information. Our analysis reveals three possible mechanisms of 1/f noise in chalcogenide glasses: mobility fluctuations due to transitions in the double-well potentials of the glass, concentration fluctuations due to the same, and generation-recombination noise due to multiphonon electronic transitions in the quasicontinuous spectrum of electronic states in the mobility gap. We show that double-well potentials are the most likely source of the observed 1/f noise. Furthermore, we discriminate between the double-well potentials of atomic and electronic nature. The latter are related to the spatially close (intimate) pairs of oppositely charged negative-U centers and provide a much stronger effect on the 1/f noise. Our theory gives explicit expressions for the noise amplitude and the Hooge parameters corresponding to all mechanisms of 1/f noise in chalcogenide glasses. Most of these expressions are obtained in both a simplistic intuitive way and by means of much more involved rigorous analysis provided in the paper's Appendixes.