The invention relates to a preparation method of an improved type back surface tunnel oxidization and
passivation contact efficient battery. The preparation method comprises the steps of performing texturing after a
silicon wafer damage layer is removed; next, forming a low
surface concentration B doped P<+> emitting junction; after performing edge insulating and back surface
polishing, enabling ultra-thin tunnel
oxide layer SiO<2> and P-doped polysilicon layer to be grown on the back surface of a
silicon wafer; depositing an
aluminium oxide layer on the surface of the P<+> emitting junction;enabling a hydrogenated
amorphous silicon nitride passivated antireflection layer to be grown on the front surface of the
silicon wafer; forming partial heavy
doping on the back surface of the siliconwafer by adopting a
laser doping or wet
etching method; enabling the hydrogenated
amorphous silicon nitride passivated antireflection layer to be grown on the back surface of the silicon wafer; and finally, printing Ag / Al paste on the front surface of the silicon wafer, and printing Ag paste on the back surface. By adoption of the layer of the ultra-thin tunnel
oxide layer SiO<2>, one layer of
phosphorus P-doped silicon layer and the P-doped region partial heavy
doping, the
metal-
semiconductor surface compounding on the back surface can be greatly lowered; and the preparation method has the most obvious
advantage of capability of greatly improving
electrical performance on the basis of compatibility with the conventional battery manufacturing process.