Patent ID: 7282780

Claim:
A capacitor comprising: a semiconductor substrate having a first type of conductivity and including a surface; a first well having a second type of conductivity and formed in the surface of the semiconductor substrate; a second well, having the second type of conductivity, formed in the first well and including a surface; a first diffusion layer, having the first type of conductivity and including an edge, formed on the surface of the second well; a second diffusion layer, formed in the second well, having the first type of conductivity and a concentration lower than that of the first diffusion layer and surrounding the first diffusion layer; a capacitor insulation film formed on the first diffusion layer and the second diffusion layer; a field insulation film surrounding the capacitor insulation film, the field insulation film including an edge adjacent to the capacitor insulation film, and the edge of the field insulation film being entirely spaced from the edge of the first diffusion layer; and an electrode formed on the capacitor insulation film and opposed to the first diffusion layer.