Application of Phosphorus-Doped Polysilicon-Based Full-Area Passivating Contact on the Front Textured Surface of p-Type Silicon

A p-type crystalline silicon (c-Si) passivated emitter and rear contact (PERC) nowadays have become mainstream in the highly competitive photovoltaic market. Herein, the recently popular passivating contact concept on the front textured surface of p-type c-Si PERC solar cells is applied. The full-area textured passivating contact consists of an ultrathin SiO₂ film of ≈1.5 nm thickness grown with thermal oxidation and phosphorus-doped polysilicon (poly-Si) contact layer by low-pressure chemical vapor deposition. A detailed investigation of poly-Si with different crystalline structures, doping conditions, and thicknesses on the passivation effect and parasitic absorption loss is carried out. Preliminary achievement of 21.3% efficiency is realized in large-area (244.3 cm²) p-PERC c-Si solar cells without the need for additional laser selective redoping. Theoretical calculation expects that the cell efficiency can be enhanced to 23.4% by decreasing the recombination current to a reasonable level. It is demonstrated that further improvement of low-cost p-PERC c-Si solar cells is feasible using the full-area textured passivating contact processes which are fully compatible with existing production lines.