Semiconductor device and method for manufacturing same

A semiconductor device comprising:

• a semiconductor substrate having a diode formation region;
• an upper diffusion region of a first conductivity type provided on a surface layer of a main surface of the semiconductor substrate in the diode formation region;
• and
• a lower diffusion region of a second conductivity type provided at a position deeper than the upper diffusion region with respect to the main surface in a depth direction of the semiconductor substrate, the lower diffusion region having a higher impurity concentration as compared to the semiconductor substrate,
• wherein the lower diffusion region provides a PN junction with the upper diffusion region at a position deeper than the main surface, and has a maximum point indicating a maximum concentration in an impurity concentration profile of the lower diffusion region in the diode formation region,
• wherein the upper diffusion region and the lower diffusion region are distributed in rotational symmetry with a virtual line as a symmetry axis, which passes through the maximum point and follows the depth direction,
• wherein the PN junction has a recessed surface around the symmetry axis such that at least a portion of the upper diffusion region is recessed toward the main surface of the semiconductor substrate, and
• wherein the symmetry axis passes through a center of the recessed surface, and a distance between the recessed surface and the main surface shortens along a continuous curvature of the recessed surface approaching the center of the recessed surface.