Wet etching method for an N-type bifacial cell

摘要

The present invention discloses a wet etching method for an N-type bifacial cell including: (1) providing an N-type silicon wafer, proceeding with surface structuralization on the N-type silicon wafer, and producing a PN junction on a surface 5 of the N-type silicon wafer by using a boron diffusion technique; (2) proceeding with a first mixed acid washing, etching the PN junction on an edge and a back surface of the N-type silicon wafer; (3) proceeding with a first pure water washing and a first alkaline washing, removing residual acid solution from the surface of the N-type silicon wafer; (4) proceeding with a second pure water washing and a second mixed acid washing, 10 removing residual impurities from the surface of the N-type silicon wafer; (5) proceeding with a third pure water washing and air drying; and (6) after air drying, completing etching on the N-type bifacial cell. Under the premise of assuring the cell efficiency is not reduced, the present invention increases the polishing passivation effect on the back surface to increase the optical-electrical conversion efficiency of the N-type 15 bifacial cell. Furthermore, increasing the etching on the edge and the back surface removes the PN junction diffused to the edge of the N-type silicon wafer during the boron diffusion procedure, avoiding the leakage problem on the edge of the N-type bifacial cell product.