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

- 21.7% large area (15.6×15.6 cm2) IBC devices obtained.
- Simplified process flow.
- In-depth analysis of recombination and optical losses.
- Numerical optimization.

In this paper we propose a possible process simplification for pseudosquare 15.6×15.6 cm2 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 SiNx 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 cm2. Further characterization implies that cells were limited mainly by: i) FF losses attributed to lateral majority carrier transport in the BSF region and increased J02 losses, ii) current loss which can be related to the BSF region.