New Insights into Processes of Hydrogen Incorporation and Hydrogen Diffusion in Hydrogenated Amorphous Silicon

Abstract

By secondary ion mass spectrometry profiling, the incorporation and the diffusion of hydrogen in undoped plasma-deposited hydrogenated amorphous silicon (a-Si:H) films were studied as a function of hydrogen concentration. The results show that in the range between 1 and 10 at% a structure-related hydrogen solubility limits the hydrogen incorporation. The observed concentration dependence of the hydrogen diffusion coefficient can be explained by a band model of hydrogen diffusion involving a rather mobile hydrogen chemical potential for material of low hydrogen concentration.