Investigation on Blistering Behavior for n-type Silicon Solar Cells

Thermal treatment with different gas environment before the Al₂O₃ ALD passivation process plays a key role to the presence of blistering. The specific silanol group vibration peaks in FT-IR spectra confirm the mechanism of the blistering free surface formation. The blistering affects not only the appearance but also the implied Voc of the cells, that is to say, the quality of the passivation [10]. The hydrogen containing species (by-product of the ALD process) will bond to the SiO₂ (both Si and O atom site) which grows after the thermal treatment with oxygen. Due to the good diffusivity within the SiO₂ layer, the amount of hydrogen out-diffusing towards the SiN_X ARC layer after firing can be reduced to achieve blistering free silicon solar cells.