Phosphorous diffusion method for polycrystalline silicon solar battery

Abstract

The invention discloses a phosphorous diffusion method for a polycrystalline silicon solar battery. The phosphorous diffusion method comprises the following steps of: (1) placing a silicon chip to be treated into a diffusion furnace, and raising the temperature to be between 750 and 830 DEG C; (2) when the temperature is stable, raising the temperature of each temperature area in the furnace to be between 800 and 880 DEGC, and introducing a gas carrying HCl at a speed of 0.4-3 L / min into the furnace while the temperature is raised; (3) stopping introducing the gas carrying the HCl, and only introducing dry oxygen at a speed of 0.4-3 L / min; (4) introducing a gas carrying a phosphorus source and the dry oxygen at the same time to perform diffusion; (5) stopping introducing the dry oxygen and the gas carrying the phosphorus source, and only introducing the gas carrying the HCl at a speed of 0.4-3 L / min; (6) stopping introducing the gas carrying the HCl, and only introducing the dry oxygen at a speed of 0.4-3 L / min; and (7) lowering the temperature and discharging from a boat. According to the phosphorous diffusion method, the problems of obstruction of hydrogen diffusion and the like caused by the reason that the hydrogen diffusion speed is low and the oxygen or an oxygen deposit can be combined with hydrogen in an oxygen-rich environment in the prior art are solved; and experiments prove that: compared with the prior art, the photoelectric conversion efficiency of the solar battery obtained by adopting the phosphorous diffusion method has about 0.3 percent of absolute value promotion, and an unexpected effect is achieved.

Description

technical field [0001] The invention relates to a diffusion junction process for manufacturing solar cells, in particular to a phosphorus diffusion method for polycrystalline silicon solar cells. Background technique [0002] Crystalline silicon solar cell is a device that directly converts light energy into electrical energy. Because of its cleanness, pollution-free, inexhaustible and inexhaustible, it has gradually become an important power generation method. The principle is to use the photovoltaic effect of the PN junction to convert light energy into electrical energy. [0003] At present, the manufacturing process of crystalline silicon solar cells has been standardized. The main steps are: chemical cleaning and surface structuring (texturing)—diffusion junction—peripheral etching—removal of phosphosilicate glass—deposition of anti-reflection film—printing electrodes—sintering . Among them, the diffusion junction (usually phosphorus diffusion junction) step is a key ...

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Problems solved by technology

The above factors affect the photoelectric conversion efficiency of crystalline silicon solar cells

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