New surfactants for combined cleaning and texturing of mono-crystalline silicon wafers after wire-sawing

摘要

The following paper presents a new substance with the potential to substitute 2-propanol as a texturing agent in solar cell processes with an additional cleaning capability. This allows to combine the cleaning after wire-sawing with the texturization into one single process. The substance was selected from a pool comprising 45 different organic compounds. This promising substance combines a relative good texture capability, a high etch-rate in basic solution, high process stability, low toxicity and reasonable price availability. This compilation of qualities represents relevant requirements for a texturing agent to be brought into industrial scale operation. In tandem with its cleaning functionality, this surfactant allows to perform a new sequence of processes where the texturing step can take place at the beginning of the solar cell production chain. It was proved that mono-crystalline silicon wafers processed with this surfactant acquired a higher mechanical stability than those following standard process conditions. High mechanically stable wafer manufacture together with a shortened new sequence of processes between wafering and emitter diffusion can lead to a strong reduction of breakage rate during the solar cell production