Manufacturing method of solar cell

Abstract

The present application can easily realize a selective emitter structure by including the following steps: a first step that coats a portion of one surface of a first conductive-type semiconductor substrate (2) with a paste (21) that contains a second conductive-type impurity element; a second step that, inside a processing chamber, applies a first heat treatment to the semiconductor substrate in a gas atmosphere that does not contain the second conductive type impurity element and causes diffusion of the second conductive type impurity element from the paste to the lower region of the paste on the semiconductor substrate, thereby forming in the lower region of the paste on the semiconductor substrate a first impurity diffusion layer (3a) in which the second conductive type impurity element is diffused at a first concentration; and a third step that, inside the processing chamber, following the first heat treatment, applies a second heat treatment to the semiconductor substrate in a gas atmosphere that contains a dopant that contains the second conductive type impurity element and causes diffusion of the second conductive type impurity element from the gas containing the dopant to an exposed region not coated with paste on the one side of the semiconductor substrate, thereby forming on the exposed region a second impurity diffusion layer (3b) in which the second conductive type impurity element is diffused at a second concentration, which is lower than the first concentration.

Description

technical field [0001] The present invention relates to a method of manufacturing a solar cell. Background technique [0002] In general monocrystalline silicon solar cells or polycrystalline silicon solar cells, it is necessary to form a pn junction in order to separate carriers generated by irradiation with sunlight. For example, when a p-type silicon substrate is used as the substrate, a pn junction is formed by diffusing group 5 elements such as phosphorus to the light-receiving side of the substrate to form an n-type silicon layer on the light-receiving side of the substrate. The impurity element diffused into the substrate in this way is called a dopant. [0003] That is, when a p-type monocrystalline silicon substrate or a p-type polycrystalline silicon substrate is used as the substrate, the phosphorus-based dopant is thermally diffused to the light-receiving surface side of the substrate at a temperature of about 700°C to 1000°C, thereby Diffusion layers are forme...

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Problems solved by technology

[0011] However, according to the above-mentioned prior art, there are problems in that either a dedicated device is required, or a plurality of complicated processes need to be performed, and the maintenance of the device is also difficult.

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