Patent ID: 11949031
Assignee: TONGWEI SOLAR (MEISHAN) CO., LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 0:
1. A preparation method for a p-type bifacial solar cell with partial rear surface field passivation, comprising following steps:
S1: selecting a p-type silicon substrate, cleaning the p-type silicon substrate, and performing surface polishing;
S2: performing low-pressure thermal diffusion on an upper surface of the p-type silicon substrate to prepare a phosphorus source doped layer;
S3: performing ozone oxidation on a lower surface of the p-type silicon substrate to grow a silicon oxide passivation layer;
S4: preparing a front-surface silicon nitride antireflection layer on an upper surface of the phosphorus source doped layer;
S5: preparing an aluminum oxide passivation layer on a lower surface of the silicon oxide passivation layer;
S6: preparing a back-surface silicon nitride antireflection layer on a lower surface of the aluminum oxide passivation layer;
S7: using a laser on a lower surface of the back-surface silicon nitride antireflection layer to form several local grooves, wherein the several local grooves are all grooved to the lower surface of the p-type silicon substrate, and a depth of the several local grooves measured from the lower surface of the p-type silicon substrate is in the range of 500 nm-1500 nm, and a spacing between the several local grooves is in the range of 1 um-3 um, and then preparing boron source doped layers by screen printing boron source slurry in the several local grooves until a lower surface of the boron source doped layers is flush with the lower surface of the p-type silicon substrate, and main components of the boron source slurry comprise boric acid with a concentration of 50%-70% and tributyl borate with a purity of 60%-90%;
S8: performing screen printing on the lower surface of the boron source doped layers in the several local grooves to prepare a back-surface metal electrode layer, wherein the back-surface metal electrode layer successively passes through the silicon oxide passivation layer, the aluminum oxide passivation layer and the back-surface silicon nitride antireflection layer; and
S9: performing screen printing, on an upper surface of the front-surface silicon nitride antireflection layer to prepare a front-surface metal electrode layer.