Dave Savastano09.25.14
At the European Photovoltaic Solar Energy Conference and Exhibition (EU PVSEC 2014), imec and RENA, a leading supplier for wet chemical production tools, presented a novel isopropyl-alcohol (IPA)-free process for the texturing of Cz-Si wafers for high-efficiency silicon solar cell manufacturing at low cost.
The process uses monoTEX F, RENA’s next generation texturing additive, instead of the currently used industrial additive IPA. In contrast monoTEX F is a moderating and wetting agent that behaves almost “linear” towards changes in process temperature and alkali concentration and operates at temperatures far below its boiling point . It will thus not evaporate, resulting in stable concentration of ratios in the etching mixture during the texturing process step.
As a result, monoTEX F based texturing simplifies the texturing of Cz-silicon wafers, widens the texturing process window and increases texturing bath lifetime (i.e. more wafers can be processed in a single texturing bath compared to state-of-the-art IPA-based texturing).
“When applying this novel monoTEX F-based texturing in our Si PV pilot line to process large area (156x156 mm2) PERC-type solar cells, we achieved excellent conversion efficiencies well above 21%,” said Dr. Joachim John, R&D project manager at imec. “We are confident that RENA’s monoTEX F-based texturing process is an excellent candidate to be considered for next generation high volume Cz-silicon solar cell manufacturing.”
“The achieved uniformity and reflection data from imec are consistent with mass production data,” Dr. Jürgen Schweckendiek, R&D project manager at RENA, added.
The process uses monoTEX F, RENA’s next generation texturing additive, instead of the currently used industrial additive IPA. In contrast monoTEX F is a moderating and wetting agent that behaves almost “linear” towards changes in process temperature and alkali concentration and operates at temperatures far below its boiling point . It will thus not evaporate, resulting in stable concentration of ratios in the etching mixture during the texturing process step.
As a result, monoTEX F based texturing simplifies the texturing of Cz-silicon wafers, widens the texturing process window and increases texturing bath lifetime (i.e. more wafers can be processed in a single texturing bath compared to state-of-the-art IPA-based texturing).
“When applying this novel monoTEX F-based texturing in our Si PV pilot line to process large area (156x156 mm2) PERC-type solar cells, we achieved excellent conversion efficiencies well above 21%,” said Dr. Joachim John, R&D project manager at imec. “We are confident that RENA’s monoTEX F-based texturing process is an excellent candidate to be considered for next generation high volume Cz-silicon solar cell manufacturing.”
“The achieved uniformity and reflection data from imec are consistent with mass production data,” Dr. Jürgen Schweckendiek, R&D project manager at RENA, added.