Phosphoric Anti-Reflective Coatings as Dopant Source and Front-Side Passivation for Industrial Silicon Solar Cell Manufacturing

In this paper, we present the development and investigation of a multifunctional stack-layer plasma deposition for silicon solar cells. The thin stack layer works as phosphorous source in high-temperature diffusion and remains afterwards as front surface passivation and anti-reflective coating (ARC). This way the production of solar cells can be significantly simplified as the wet-chemical removal of phosphosilicate glass (PSG) becomes redundant and the diffusion step could be realised without a POCl3 atmosphere in an open inline furnace system. In this study it is shown that it is possible to deposit such a layer in an industrial-type PECVD system using a double-layer stack of a thin PSG layer and a silicon nitride capping layer. The investigated process steps results in an emitter saturation current j0e < 120 fA/cm2 for a emitter sheet resistance of RE < 65 /sq..