Abstract: A horizontal transfer section is formed on a P-type semiconductor substrate. A floating diffusion layer for receiving signal charges from the horizontal transfer section and a detector MOSFET for detecting any potential change of the floating diffusion layer are further formed. This detector MOSFET has a gate electrode in which an opening is formed. The gate electrode extends toward the floating diffusion layer and the opening is positioned above the floating diffusion layer. As a result, a solid-state image sensor constituted as above, can reduce the area of the floating diffusion layer and can detect signal charges at high sensitivity.

Abstract: In a semiconductor device, in order to protect an interior of the device, protective circuits are provided. The protective circuits include a first circuit connected between the first terminal and a negative potential line, a second circuit connected between the first terminal and a ground potential line, and a third circuit connected between the ground potential line and a second terminal. The first circuit consists of a MOS transistor having a drain connected with the first terminal, a source connected with the negative potential line, and a gate connected with the first terminal or the negative potential line. The second circuit consists of a MOS transistor having a drain connected with the first terminal, a source connected with the ground potential line, and a gate connected with the first terminal or the ground potential line.

Abstract: There is provided a solid state imaging device having high-sensitivity, low-noise characteristics by reducing electrostatic capacity relating to interconnection. The solid state imaging device includes a photoelectric conversion section, a transfer section, a floating diffusion layer for receiving signal charges from the transfer section, and an output transistor having a gate electrode connected to the floating diffusion layer via an interconnection. A source and a drain of the output transistor are provided commonly within a flat p-type well of relatively thin concentration in which the photoelectric conversion section, the transfer section, and the floating diffusion layer are also provided.