SIMS depth profile analysis for investigations of the lithium-diffusion in hydrogenated amorphous silicon

Summary SIMS depth profiling, using an oxygen primary beam at close to normal incidence, was applied to study lithium diffusion in thin films of hydrogenated amorphous silicon (a-Si:H) as well as in layered structures of doped and undoped silicon-based alloys. A strongly increasing decay length of the lithium profiles was observed for increasing primary beam energies and is attributed to the Li accumulation at the SiO_x/Si interface. The stability of the lithium incorporation in a-Si:H is found to depend on the presence of charged acceptors or defects and of doping gradient related electrical fields.