Contacting n+ Poly-Si Junctions with Fired AZO Layers: A Promising Approach for High Temperature Passivated Contact Solar Cells
Elise Bruhat1, Thibaut Desrues1, Danièle Blanc Pélissier2, Benoît Martel1, Raphaël Cabal1, Sébastien Dubois1
1CEA-INES, Le bourget du Lac, France
/2INL, Villeurbanne, France

Polysilicon (poly-Si) based passivating contacts are promising to improve silicon solar cells conversion efficiency. However, the use of Transparent Conductive Oxides (TCO) has to be considered to improve lateral conductivity while maintaining good optical and surface passivation properties. In this work different Aluminum-doped Zinc Oxide (AZO) based contacts have been investigated after high temperature firing steps to contact Phosphorus-doped poly-Si layers. Good conductivity of the AZO layer have been maintained thanks to aluminum oxide capping layers. Finally, contact resistivity below 100 mΩ.cm2 at the AZO/n+ poly-Si interface and stable implied open circuit voltage (> 715 mV)  have been obtained for firing temperatures from 550°C to 850°C. This novel high temperature contacting method via indium-free TCOs, is particularly interesting for the industrial integration of poly-Si based passivated contacts.