Patent ID: 7550850

Claim:
A semiconductor device with a first device region and a second device region, comprising: a semiconductor substrate, an insulating interlayer formed on said semiconductor substrate, and an annular guard ring consisting of a conductive film buried in said insulating interlayer and surrounding the periphery of said first device region, wherein a nonconducting part blocking electric conduction in a path from said first device region, through said annular guard ring to said second device region is formed in a guard ring forming region, wherein there is formed a first diffusion layer having a same conductivity type as that in said semiconductor substrate in the vicinity of a surface of said semiconductor substrate; a second diffusion layer having an opposite conductivity type to that of said semiconductor substrate is formed in contact with a bottom surface of said first diffusion layer; a lateral periphery of said first diffusion layer is insulated; said annular guard ring is connected to a surface of said first diffusion layer; and said bottom surface of said first diffusion layer and a bottom surface of said second diffusion layer constitute said nonconducting part.