Abstract: A laser annealing apparatus according to an embodiment includes a laser light source, an annealing optical system, a linear irradiation region along a Y-direction, a moving mechanism configured to change a relative position of the irradiation region with respect to the substrate along an X-direction, an illumination light source configured to generate illumination light for illuminating the substrate along a third direction, and a detector configured to detect detection light reflected, in a fourth direction, on the substrate illuminated by the illumination light so as to photograph an annealed part of the substrate in a linear field of view along the Y-direction. In a YZ-plane view, the third direction is inclined from the vertical direction and the fourth direction is inclined from the vertical direction.

Abstract: The present invention provides a boron diffusion layer forming method capable of sufficiently oxidizing a boron silicide layer formed on a silicon substrate to remove it and obtaining a high-quality boron silicate glass layer. The present invention is a boron diffusion layer forming method of forming a boron diffusion layer on a silicon substrate by a boron diffusion process, the process including a first step of thermally diffusing boron on the silicon substrate and a second step of oxidizing a boron silicide layer formed on the silicon substrate at the first step, wherein the second step has a state at a temperature of 900° C. or higher and a treatment temperature at the first step or lower, for 15 minutes or more.

Abstract: The present invention provides a boron diffusion layer forming method capable of sufficiently oxidizing a boron silicide layer formed on a silicon substrate to remove it and obtaining a high-quality boron silicate glass layer. The present invention is a boron diffusion layer forming method of forming a boron diffusion layer on a silicon substrate by a boron diffusion process, the process including a first step of thermally diffusing boron on the silicon substrate and a second step of oxidizing a boron silicide layer formed on the silicon substrate at the first step, wherein the second step has a state at a temperature of 900° C. or higher and a treatment temperature at the first step or lower, for 15 minutes or more.

Abstract: [Problem] To provide a solar battery cell such that higher conversion efficiency than ever before is achieved and conversion efficiency of its front surface and conversion efficiency of its rear surface become almost equivalent in a double-sided light-receiving type solar battery cell. [Solution] There is provided a solar battery cell including: an n-type silicon substrate having a thickness of not less than 100 ?m nor more than 250 ?m; a p-type diffusion layer formed on a first light-receiving surface being a front surface of the silicon substrate; an n-type diffusion layer formed on a second light-receiving surface being a rear surface of the silicon substrate; an anti-reflection film formed on the p-type diffusion layer and the n-type diffusion layer; a plurality of grid electrodes and a plurality of busbar electrodes that are formed on part of the p-type diffusion layer; and a plurality of grid electrodes and a plurality of busbar electrodes that are formed on part of the n-type diffusion layer.