Semiconductor device

A semiconductor device comprising:

• a chip that has a first principal surface and a second principal surface at an opposite side thereto of quadrangle plan view shapes;
• an active region that is provided in the first principal surface and has an element structure formed therein;
• an outer peripheral region that is a region outside the active region, is provided in an outer peripheral portion of the first principal surface, and has four corner portions;
• a drift region of a first conductivity type that is formed in an interior of the chip;
• and
• a plurality of field limiting rings (referred to hereinafter as “FLRs”) of a second conductivity type that are formed in a surface layer portion of the first principal surface in the outer peripheral region such as to surround the active region;
• and
• wherein each of the FLRs has FLR curve portions, each being of a curve shape in plan view shape, in the four corner portions,
• each of the FLRs has FLR rectilinear portions, each being of a rectilinear shape in plan view shape, between the four corner portions, and
• each of the FLR curve portions has a double-diffused structure including a first diffusion region at an inner side and a second diffusion region at an outer side that is lower in impurity concentration of the second conductivity type than the first diffusion region.