The invention relates to the field of an N-type
solar battery, particularly the N-type
solar battery prepared by a film masking process of one multi-purpose film and a preparation method of the N-type
solar battery. The N-type solar battery has the structure that: an n-type straight-pull
monocrystalline silicon is used as a substrate, the backside of a
silicon sheet is a P-type emitter junction prepared by
boron diffusion of a SiO2 and SiNx coated dual-layer
passivation film, and the front side of the
silicon sheet is a front
surface field prepared by phosphorous
diffusion and a thin film playing a
passivation and reflection reduction role covers on the front
surface field. The preparation method of the N-type solar battery comprises the following steps of: with the n-type straight-pull
monocrystalline silicon as the substrate, preparing the P-type emitter junction by the
boron diffusion firstly, and then
etching the P-type emitter junction on the front side; preparing the SiO2 film on the P-type emitter junction on the backside of the
silicon sheet, wherein the SiO2 film is not only a
mask film for preparing the front
surface field by the phosphorous diffusion subsequently, but also the
passivation film of the P-type emitter junction; and lastly, preparing the front surface field by the phosphorous diffusion. The invention has the advantages of simple technique process, easy control, low cost and high
photoelectric conversion efficiency.