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. A tunneling oxide passivation contact (TOPCON) structure with full‐area passivation is deposited on the front surface of passivated emitter/rear contact solar cells. Ultrathin SiO2 film possess the thickness of ≈1.5 nm grown with thermal oxidation. The drive‐in time of phosphorus diffusion is optimized to improve passivation. Preliminary achievement of 21.3% efficiency in large‐area (244.3 cm2) is realized.