Diffusion of hydrogen in silicon: Diffusion-reaction model

A diffusion-reaction model is proposed as the mechanism for the diffusion of hydrogen in amorphous and crystalline silicon. In this model molecular hydrogen dissolves and diffuses interstitially in the open silicon structure. Dissolved molecular hydrogen reacts with silicon to form SiH groups. Equations derived for this model give profiles that fit well with experimental hydrogen profiles in amorphous silicon. Other experimental features, such as steps in hydrogen and deuterium concentrations at interfaces, exponential profiles at short times, and a decrease of the: effective diffusion coefficient with increasing time arise naturally in the diffusion-reaction model.