From nano-voids to blisters in hydrogenated amorphous silicon

AFM and FTIR spectroscopy were applied to study the relationship between surface blisters and nanovoids in annealed hydrogenated a-Si. The influence of the H bonding configuration on the way the nanovoids give rise to the blisters is discussed. Annealing causes an increase of the polymers density. As they reside on the voids walls their density increase causes an increase of the voids volume. The polymers may release H inside the voids with creation of H2 gas, whose expansion, upon annealing, further contributes to the volume increase of the voids till the formation of surface blisters.