Aromatic compounds as substitutes for 2-propanol as texturing additive in aqueous alkaline solutions
Two aromatic organic substances, a micelles-forming agent, an aromatic acid, and a complex-forming agent, an aromatic alcohol, were tested on 50 mm x 50 mm Cz-Si-wafers as texturing agents for mono-crystalline silicon solar cells according to the weighted reflectance of the processed surfaces and the etch-rates of the texturing-solutions in dependence of their composition. The results were compared with those of the standard organic texturing agent 2-propanol (iso-propanol, IPA). It could be shown, that the aromatic acid can compete with IPA as texturing additive while etching solutions based on the aromatic alcohol were less successful. After that the system containing the aromatic acid was tested on large number of 125 mm x 125 mm Cz-Si-wafers in an industrial pilot production line of Innovalight Inc., where even better results were reached in shorter time-scales in comparison with the standard texturing process.