Selective doping method for n-type solar cells

Abstract

The invention discloses a selective doping method for N-type solar cells. Boron paste is used as the diffusion source in the heavily doped region, and a gas phase boron source is used as the diffusion source in the lightly doped region; Oxide layer, and then cover the second oxide layer on the printed boron paste, which is blocked by two layers of oxide layer, so as to reduce the expansion of boron paste and reduce the doping amount of the lightly doped area; and when advancing at high temperature, the difference In the way of chemical advancement, the heavily doped area with boron slurry as the boron source is advanced first, and then the gas-phase boron source is ventilated, and the heavily doped area and the lightly doped area are jointly promoted to achieve a distinct distribution of heavy and light doping.

Description

technical field

[0001] The invention relates to the field of photovoltaics, in particular to a selective doping method for N-type solar cells. Background technique

[0002] The front surface of a traditional solar cell is divided into two areas, one is the area in contact with the electrode paste, and the other is the illuminated area, that is, the area without electrode paste coverage. In the preparation of the emitter of the existing solar cell, a uniformly doped emitter is generally used, that is, the metal paste contact area and the illumination area are uniformly doped. This doping method is simple and fast, but it has disadvantages. In the metal paste contact area, we need high doping concentration to reduce the metal-semiconductor contact resistance and contact recombination; in the illuminated area, we need low doping concentration to reduce the surface R Intermittent recombination, improve carrier collection rate, improve short-wave response, and improve passivatio...