Semiconductor device having electrode pad, and wireless circuit device including the semiconductor device

A semiconductor device comprising:

• a layered region formed in a semiconductor substrate of a first conductivity type;
• an electrode pad formed on the semiconductor substrate with an interlayer insulating film interposed therebetween and placed above the layered region;
• and
• a conductive film formed in the semiconductor substrate and surrounding a periphery of the layered region, wherein
• the layered region includes:
• a first impurity diffusion region;
• a second impurity diffusion region formed on the first impurity diffusion region;
• and
• a third impurity diffusion region formed on the first impurity diffusion region and surrounding a periphery of the second impurity diffusion region,
• a conductivity type of the first impurity diffusion region and a conductivity type of the third impurity diffusion region are a second conductivity type,
• a conductivity type of the second impurity diffusion region is the first conductivity type,
• an impurity concentration of the third impurity diffusion region is higher than an impurity concentration of the first impurity diffusion region, and
• the third impurity diffusion region is electrically connected to a terminal fixed to a constant potential.

A semiconductor device comprising:

• a layered region formed in a semiconductor substrate of a first conductivity type;
• an electrode pad formed on the semiconductor substrate with an interlayer insulating film interposed therebetween and placed above the layered region;
• and
• an insulating film formed in the semiconductor substrate and surrounding a periphery of the layered region, wherein
• the layered region includes:
• a first impurity diffusion region;
• a second impurity diffusion region formed on the first impurity diffusion region;
• and
• a third impurity diffusion region formed on the first impurity diffusion region and surrounding a periphery of the second impurity diffusion region,
• a conductivity type of the first impurity diffusion region and a conductivity type of the third impurity diffusion region are a second conductivity type,
• a conductivity type of the second impurity diffusion region is the first conductivity type,
• an impurity concentration of the third impurity diffusion region is higher than an impurity concentration of the first impurity diffusion region, and
• the third impurity diffusion region is electrically connected to a terminal fixed to a constant potential.