Photolithography free inverted pyramidal texturing for solar cell applications

We have demonstrated a novel process for the fabrication of inverted pyramidal structures on Silicon. The proposed technique does not use any photolithography step and is instead replaced by a thin film deposition step and thermal annealing. In this work, Inductively Coupled Plasma CVD(ICP-CVD) silicon nitride was used as the thin film. The blisters are formed upon annealing and the silicon nitride film remaining on the surface act as an etch mask for the texturization process which is carried out in alkaline solution. The impact of blistering process on the silicon wafer surface is reported. The role of silane flow, annealing temperature and time on the blistering shape, size and density is also reported.