Semiconductor device

A semiconductor device that is a facedown mountable, chip-size-package type semiconductor device, the semiconductor device comprising:

• a semiconductor layer that includes a semiconductor substrate on a back face side and is divided into a first region, a second region, and a third region that do not overlap each other and are not dispersedly disposed in a plan view of the semiconductor device;
• a first vertical metal-oxide semiconductor (MOS) transistor an entirety of which is provided in the first region of the semiconductor layer;
• a second vertical MOS transistor an entirety of which is provided in the second region of the semiconductor layer;
• a third vertical MOS transistor an entirety of which is provided in the third region of the semiconductor layer;
• and
• a metal layer that is provided in contact with the back face side of the semiconductor layer,
• wherein the semiconductor substrate is a common drain region of the first vertical MOS transistor, the second vertical MOS transistor, and the third vertical MOS transistor,
• in the plan view, a first source pad and a first gate pad of the first vertical MOS transistor and first gate wiring connected to the first gate pad are provided at positions within the first region,
• in the plan view, a second source pad and a second gate pad of the second vertical MOS transistor and second gate wiring connected to the second gate pad are provided at positions within the second region,
• in the plan view, a third source pad of the third vertical MOS transistor and third gate wiring are provided at positions within the third region,
• the first gate wiring and the third gate wiring are electrically connected in series via a first diode in a direction from the first gate wiring to the third gate wiring as a forward direction, and
• the second gate wiring and the third gate wiring are electrically connected in series via a second diode in a direction from the second gate wiring to the third gate wiring as a forward direction.