Abstract: A solar cell includes an n-type semiconductor substrate having a p-n junction and a back-surface side impurity-diffusion layer. The back-surface side impurity-diffusion layer is formed on a light-receiving surface of the semiconductor substrate or surface layer on a back-surface side opposite to the light-receiving surface, and has back-surface side high-concentration impurity-diffusion layers each of which contains an n-type or p-type impurity element at a first concentration and a back-surface side low-concentration impurity-diffusion layer which contains an impurity element of the same conductivity type as a conductivity type of the back-surface side high-concentration impurity-diffusion layers at a second concentration lower than the first concentration.

Abstract: A solar cell includes: a first-conductivity-type semiconductor substrate that includes an impurity diffusion layer on one surface side, which is a light receiving surface side, the impurity diffusion layer having a second-conductivity-type impurity element diffused therein; a plurality of linear light-receiving-surface-side electrodes that are a paste electrode that has a multi-layered structure, is formed by multi-layer printing of an electrode material paste on the one surface side, and is electrically connected to the impurity diffusion layer and that extend in parallel in a specific direction in a plane direction of the semiconductor substrate; and a back-surface-side electrode that is formed on another surface side of the semiconductor substrate. In the light-receiving-surface-side electrodes, the light-receiving-surface-side electrodes get smaller in width as they get closer in a width direction of the light-receiving-surface-side electrodes to a specific reference position.

Abstract: A solar cell includes a p-type impurity diffusion layer formed on one side of an n-type single-crystal silicon substrate, an n-type impurity diffusion layer formed on the opposite side of the substrate with an n-type impurity element at a higher concentration than the substrate, and having a first layer with an n-type impurity element diffused at a first concentration, and a second layer with an n-type impurity element diffused at a second concentration lower than the first concentration, on-p-type-impurity-diffusion-layer electrodes formed on the p-type impurity diffusion layer, and on-n-type-impurity-diffusion-layer electrodes formed on the first layer. The concentration of the n-type impurity element at a surface of the first layer is between 5×1020 atoms/cm3 and 2×1021 atoms/cm3 inclusive, and the concentration of the n-type impurity element at a surface of the second layer is between 5×1019 atoms/cm3 and 2×1020 atoms/cm3 inclusive.

Abstract: A manufacturing method of a solar cell having diffusion layers of different conductivity types on a front surface of a semiconductor substrate and a back surface thereof, respectively, includes a step of forming a diffusion protection mask containing impurities to cover at least a partial region of the semiconductor substrate, and a diffusion step of performing a diffusion step including a thermal step in a state where at least the partial region of the semiconductor substrate is covered with the diffusion protection mask containing impurities, forming a first-impurity diffusion layer in a first region covered with the diffusion protection mask, and forming a second-impurity diffusion layer having a different impurity concentration or a different conductivity type from that of the diffusion protection mask in a second region exposed from the diffusion protection mask.

Abstract: When a high-concentration diffusion layer is formed in part of a first surface of a substrate in which a diffusion layer of the light receiving surface is formed, the thermal oxidation is performed in a state where a diffusion source is formed, thereby introducing the impurity in the outermost surface of the diffusion layer of the light receiving surface into a thermal oxide film. Consequently, the outermost surface of the diffusion layer of the light receiving surface has an impurity concentration lower than that on the inner side.

Abstract: A solar cell includes: a first-conductivity-type semiconductor substrate that includes an impurity diffusion layer on one surface side, which is a light receiving surface side, the impurity diffusion layer having a second-conductivity-type impurity element diffused therein; a plurality of linear light-receiving-surface-side electrodes that are a paste electrode that has a multi-layered structure, is formed by multi-layer printing of an electrode material paste on the one surface side, and is electrically connected to the impurity diffusion layer and that extend in parallel in a specific direction in a plane direction of the semiconductor substrate; and a back-surface-side electrode that is formed on another surface side of the semiconductor substrate. In the light-receiving-surface-side electrodes, the light-receiving-surface-side electrodes get smaller in width as they get closer in a width direction of the light-receiving-surface-side electrodes to a specific reference position.

Abstract: An n-type impurity diffusion layer includes a plurality of linear first n-type impurity diffusion layers and a second n-type impurity diffusion layer. The first n-type impurity diffusion layers extend in parallel in a specific direction, are disposed in a lower region under surface silver grid electrodes and a peripheral region that extends from the lower region, and contain an impurity element at a first concentration. The second n-type impurity diffusion layer contains the impurity element at a second concentration, which is lower than the first concentration. In the first n-type impurity diffusion layers, the first n-type impurity diffusion layers get smaller in width as they get closer in a width direction of the first n-type impurity diffusion layers to a specific reference position.

Abstract: A manufacturing method of a solar cell having diffusion layers of different conductivity types on a front surface of a semiconductor substrate and a back surface thereof, respectively, includes a step of forming a diffusion protection mask containing impurities to cover at least a partial region of the semiconductor substrate, and a diffusion step of performing a diffusion step including a thermal step in a state where at least the partial region of the semiconductor substrate is covered with the diffusion protection mask containing impurities, forming a first-impurity diffusion layer in a first region covered with the diffusion protection mask, and forming a second-impurity diffusion layer having a different impurity concentration or a different conductivity type from that of the diffusion protection mask in a second region exposed from the diffusion protection mask.