A kind of preparation method of se solar cell

Abstract

The invention discloses an alkali polishing method for an SE battery. P-type silicon is made into cashmere; phosphorus is diffused to form a PSG layer on the surface of a silicon chip, that is, an N-type emitter is formed; the oxidation time is 5min-30min, and the oxygen flow rate is 1000-5000slm / min; Protect the front PSG layer and remove the back PSG layer; alkali polish the back to protect the front PSG layer from corrosion; use the front PSG layer as an impurity source for laser doping, and then remove the front PSG layer; deposit aluminum oxide film on the back; Silicon nitride anti-reflection coating on the back; laser groove on the back; back electrode printed on the back; aluminum back field printed on the back; positive electrode printed on the front; high temperature sintering. In the backside alkali polishing process of the present invention, the front laser-doped position is protected by the PSG layer, and will not be partially polished by the alkali solution, thereby ensuring the SE battery structure and improving the SE battery quality, so that the backside alkali polishing process can be popularized and applied.

Description

technical field [0001] The invention relates to a preparation method of an SE solar cell. Background technique [0002] The development direction of solar cells is low cost and high efficiency. Selective emitter technology (selective emitter, SE) is one of the methods that are expected to achieve high efficiency in the production process of crystalline silicon solar cells. SE solar cells refer to high-concentration doping at and near the contact between metal grid lines and silicon wafers, and low-concentration doping in areas other than electrodes. Such a structure not only reduces the contact resistance between the silicon wafer and the electrode, but also reduces the surface recombination, improves the minority carrier lifetime, and improves the short-circuit current, open-circuit voltage and fill factor, thereby improving the conversion efficiency. [0003] At present, SE cells are mainly realized by laser doping, that is, the phosphorus atoms in the thermally diffused ...

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Problems solved by technology

[0003] At present, SE cells are mainly realized by laser doping, that is, the phosphorus atoms in the thermally diffused PSG are redistributed by secondary diffusion through laser energy. However, this method has the following defects: the PSG located at the laser doping position It will be destroyed and cannot meet the PSG mask protection. In the back alkali polishing process, the front laser doped position will be partially polished by the alkali solution because there is no PSG or SiO2 layer, which will affect the structure of the SE battery and also restrict the back alkali polishing. app promotion for

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