Protection circuit and semiconductor device including the protection circuit

Abstract

The present invention provides a protection circuit capable of protecting a protected object from the influence of a power supply voltage of opposite polarity. The present invention is a protection circuit (20A) formed on a semiconductor substrate (50A) including a substrate region (510), a region of a first conductivity type formed on the substrate region (510), and a region of a second conductivity type formed on the substrate region (510), and protecting the protected circuit from the influence of a power supply voltage of opposite polarity to the stable state. The protected circuit includes a noise generation source and is connected to the GND terminal (2) via the protection circuit (20A) between the VDD terminal (1) and the GND terminal (2). The protection circuit (20A) includes: a first protection transistor (hereinafter, Tr) including a source and a back gate connected to the node of the first circuit; a second protection Tr including a source and a back gate connected to the node of the second circuit while remaining in a state of not being connected to the first circuit; and a partition wall (531) disposed between the first protection Tr and the second protection Tr in a direction in which the electrodes of the first protection Tr and the second protection Tr are arranged side by side.

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