Kinetics of drift and thermal diffusion of gold electrodes into amorphous semiconductor thin films

Abstract Fast and deep diffusion of metal electrode into chalcogenide amorphous semiconductor thin films has been observed below the glass transition temperature. This diffusion expressed in terms of “easy paths” is consistent with the simple model of Fisher. Complementary experiments under electrical field show that metal atoms carry positive charge and move faster, leading to different concentration profiles, obtained from α-particle backscattering experiments (up to 8 MeV). Two rates of diffusion are pointed out from the gold flux variation at the interface and from the evolution of the gold content inside the film, vs heating time. From the correlation to the electrical degradation rate of these devices, several comments are made on the possible mechanism.