Patent ID: 8362785

Claim:
A semiconductor device comprising: a well of a second conductive type formed on or above a semiconductor substrate of a first conductive type; a first diffusion layer of the second conductive type formed in a surface portion of said well; a second diffusion layer of the first conductive type formed separately from said first diffusion layer in the surface portion of said well; first to third first-layer conductive layers formed above said well; and first to third second-layer conductive layers formed above said first to third first-layer conductive layers, wherein said first second-layer conductive layer, said first first-layer conductive layer, said first diffusion layer and said well are conductively connected as a first conductive path, wherein said second second-layer conductive layer, said second first-layer conductive layer, and said second diffusion layer are conductively connected as a second conductive path, wherein said third second-layer conductive layer, and said third first-layer conductive layer are conductively connected as a third conductive path, and wherein in measurement of a capacitance between said well and said second diffusion layer, said first second-layer conductive layer is configured to be applied with a voltage, in which a small-amplitude AC voltage is superimposed on a DC bias voltage, from a measuring apparatus, said second second-layer conductive layer is configured to be connected to a ground terminal of the measuring apparatus through an ammeter, and said third second-layer conductive layer is configured to be connected to the ground terminal.