The invention provides an N type double face battery preparation method comprising the following steps: an
N type silicon chip is subjected to double face
reactive ion etching operation after undergoing damage
processing operation, and therefore a nanometer
pile face can be made on a surface; a front face of the
N type silicon chip is subjected to
boron diffusion operation after a back face of the
N type silicon chip undergoes SiOx-SiNy
mask layer
processing operation; the front face is subjected to the SiOx-SiNy
mask layer
processing operation after the SiOx-SiNy
mask layer on the back face is removed via an HF solution, an SiO2 layer is grown on the back face and used as a
mask layer, an N++ window is formed after point perforating operation is performed under a main grid, residual damage during perforation can be removed via use of weak alkali liquor, single face
phosphorus diffusion is performed on the back face of the N type
silicon chip, an N++ layer is formed at a perforated position, N+
layers are formed at other areas, and the N type
silicon chip is subjected to HF processing operation after edge isolation is conducted on the N type
silicon chip; the SiOx-SiNy
mask layer and
borosilicate glass on the front face and phosphorosilicate glass on the back face are removed; RCA cleaning operation is performed; the front face and the back face of the N type
silicon chip are respectively subjected to A12O3 / SiNx and lamination
passivation operation, and
sintering operation is conducted after
screen printing operation; via the N type double face battery preparation method, Uoc, Isc and FF can be improved;
photoelectric conversion efficiency of a front face of a battery can be improved.