Alkaline or acidic etching agents remove the surface damage induced by the sawing process and texture the surface of the wafer.

Acidic etching agents, like HF and HNO3 are used for isotropic etching. Typical alkaline etching agents are caustic soda (NaOH), caustic potash (KOH) and tetramethylammonium hydroxide (TMAH) solutions.

Wafer surface texturing is important to improve the light trapping into the cell and the energy absorption capacity. The major factors of influence in this process are the current bath concentration and residence time.