Preparation method of selective emitter of N-type battery

The invention discloses a preparation method of a selective emitter of an N-type battery. The following steps are carried out in sequence on a silicon wafer in chain type equipment: depositing boron slurry and taking the boron slurry as a doping source of a heavily doped region; performing high-temperature propulsion for the first time to enable the doping source in the heavily doped region to be diffused into the silicon wafer; depositing a liquid boron source, and taking the liquid boron source as a doping source of a lightly doped region; and performing high-temperature propulsion for the second time to enable the doping source of the heavily doped region and the doping source of the lightly doped region to be diffused into the silicon wafer. The boron slurry is used as the doping source of the heavily doped region, the liquid boron source is used as the doping source of the lightly doped region, the preparation of the emitter of the heavily doped region and the lightly doped region is realized through the