Patent ID: 8097921

Claim:
A semiconductor device comprising: a high-breakdown-voltage transistor including a semiconductor layer of a predetermined conductivity type, the semiconductor layer having front and back sides opposite to each other, the semiconductor layer including an element portion and a wiring portion that are electrically isolated from each other by a trench, wherein the element portion has a first wiring member on the front side of the semiconductor layer and a backside electrode on the back side of the semiconductor layer, the element portion being configured as a vertical transistor that causes an electric current to flow in a thickness direction of the semiconductor layer between the first wiring member; and the backside electrode, wherein the backside electrode is elongated from the element portion to the wiring portion, and wherein the wiring portion has a second wiring member on the front side of the semiconductor layer and the backside electrode on the back side of the semiconductor layer, the wiring portion being configured as a pulling wire that allows the electric current to flow between the backside electrode and the second wiring member; a low voltage circuit section; and a high voltage circuit section, wherein the high-breakdown-voltage transistor is configured to perform power conversion between the low voltage circuit section and the high voltage circuit section.