Dependence of hydrogen diffusion on growth conditions in hydrogenated amorphous silicon

The dependence of the hydrogen diffusion coefficient on the material growth conditions in doped hydrogenated amorphous silicon has been measured, using secondary-ion mass spectrometry. A greatly enhanced diffusion was found in material with a columnar microstructure because of the preferential motion of hydrogen along the columns. Increasing the deposition temperature in non-columnar material results in a higher diffusion coefficient and a lower hydrogen concentration. No significant change in the diffusion was found with different n-type dopants.