Hydrogen diffusion in polycrystalline silicon thin films

Grain boundaries in undoped polycrystalline silicon (poly-Si) thin films are shown to act as efficient hydrogen traps rather than as paths of enhanced diffusion. A comparison of hydrogen diffusion in poly-Si and undoped single-crystal silicon (c-Si) demonstrates that the diffusion in poly-Si is significantly suppressed compared to c-Si. These results have significant implications for hydrogenation of poly-Si thin-film transistors.