Crystalline silica solar cell chip diffusion method

Abstract

The invention discloses a crystalline silica solar cell chip diffusion method. Hydrofluoric acid or nitric acid is used for cleaning oil stain on the surface of a silicon chip and etching the surface of the silicon chip, the cleaned and etched silicon chip is placed in a vertical diffusion furnace to be diffused, and the diffusion technology includes following steps of (1) putting into the furnace: putting a quartz boat containing crystalline silica chips into the furnace at a uniform speed; (2) carrying out vacuum-pumping, wherein the pressure in a furnace chamber is 300 + / -50 mTorr after the step of vacuum-pumping; (3) carrying out vacuum leak detection on the furnace chamber; (4) carrying out oxidation in low pressure; (5) carrying out first phosphor source diffusion in low pressure; (6) heating; (7) carrying out second phosphor source diffusion in low pressure; (8) carrying out phosphor impurity propulsion in low pressure; (9) cooling; and (10) taking out form the furnace. By adopting the above crystalline silica solar cell chip diffusion method, the molecule free path of impurity is raised and the uniformity of diffusion of the crystalline silica chip is improved during diffusion, and the conversion efficiency of the crystalline silica solar cell chip is high; and the diffusion method is easy to operate, large in output and low in cost.

Description

technical field [0001] The invention relates to the field of production of solar cells, in particular to a method for diffusing crystalline silicon solar cells. Background technique [0002] Diffusion is an important process in the production process of crystalline silicon solar cells. The traditional diffusion process uniformly dopes the surface of crystalline silicon solar cells. High, but the high impurity concentration on the surface leads to band shrinkage in the diffusion region, lattice distortion, increased defects, obvious "dead layer", and poor short-wave response of the battery; in order to obtain high-efficiency crystalline silicon solar cells with good short-wave response, the crystalline silicon Diffusion develops in the direction of high square resistance. The current diffusion method for crystalline silicon solar cells is as follows: place the crystalline silicon wafer in a horizontal diffusion furnace cavity, and pass in a mixed gas, which is composed of ni...

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Problems solved by technology

[0002] Diffusion is an important process in the production process of crystalline silicon solar cells. The traditional diffusion process uniformly dopes the surface of crystalline silicon solar cells. High, but the high impurity concentration on the surface leads to band shrinkage in the diffusion region, lattice distortion, increased defects, obvious "dead layer", poor short-wave response of the battery; in order to obtain high-efficiency crystalline silicon solar cells with good short-wave response, the crystalline silicon wafer Diffusion develops in the direction of high square resistance

The current diffusion method for crystalline silicon solar cells is as follows: place the crystalline silicon wafer in a horizontal diffusion furnace cavity, and pass in a mixed gas, which is composed of nitrogen and phosphorus oxychloride in proportion, and is in a state of normal pressure. Diffusion of crystalline silicon wafers, the uniformity of the surface sheet resistance in the crystalline silicon wafers obtained after diffusion processing is poor, and when high surface sheet resistance is produced, it is easy to cause low-efficiency crystalline silicon solar cells in the subsequent production process

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