Full-passivation back contact TBC solar cell structure and preparation method thereof

The invention relates to the technical field of solar power generation, in particular to a full-passivation back contact TBC solar cell structure and a preparation method thereof, and the method comprises the following steps: S1, carrying out the double-side polishing of a silicon wafer; s2, a first tunneling SiO2 layer is prepared through oxidation, a layer of boron-doped amorphous silicon is deposited to form a P + poly layer, a patterned laser SiO2 mask is formed, and alkali washing is carried out; s3, a second tunneling SiO2 layer is prepared through oxidation, a layer of phosphorus-doped amorphous silicon is deposited to form a back N + poly layer, and a patterned laser SiO2 mask is formed; s4, forming a pyramid suede; s5, depositing a layer of phosphorus-doped amorphous silicon to form a front N + poly layer; s6, the silicon wafer is placed in a high-temperature annealing furnace tube, an N + front passivation field is formed on the light receiving face of the front face of the silicon wafer, and a P +