Process simplification for 15.6×15.6 cm2 interdigitated back contact silicon solar cells by laser doping.

In this paper we propose a possible process simplification for pseudosquare 15.6×15.6 cm 2 Interdigitated Back Contact (IBC) CZ-Si solar cells. By using laser doping to create a selective BSF, one out of three diffusions and a wet etching step can be avoided, compared to a completely diffusion-based process flow. We show numerical optimization of this simplified cell structure in terms of: i) rear optics with additional SiN x capping layer, ii) contact fraction of the selective BSF. The results feature a top cell efficiency of 21.7% measured over the area of 239 cm 2 . Further characterization implies that cells were limited mainly by: i) FF losses attributed to lateral majority carrier transport in the BSF region and increased J 02 losses, ii) current loss which can be related to the BSF region. [ABSTRACT FROM AUTHOR]