Insulated gate semiconductor device
An insulated gate semiconductor device includes a one conductivity type semiconductor layer, a first operation part in a surface of the semiconductor layer and a second operation part in the surface of the semiconductor layer that is smaller in area than the first operation part. A first channel region and a first transistor of an opposite conductivity type are provided in the first operation part and a second channel region and a second transistor of the opposite conductivity type are provided in the second operation part. The first operation part is disposed around the second operation part. Accordingly, design rules for four corner portions can be made uniform and depletion layer spreading in corner portions at a peripheral edge of a channel region of an operation part in application of a reverse voltage is also made approximately uniform. Thus, stable VDSS breakdown voltage characteristics can be obtained.
1. An insulated gate semiconductor device comprising:
a semiconductor layer of a first conductivity type;
a first operation part provided in a surface of the semiconductor layer;
a second operation part provided in the surface of the semiconductor layer so as to be smaller in area than the first operation part;
a first channel region of a second conductivity type opposite from the first conductivity type provided in the first operation part;
a first transistor provided in the first operation part and comprising a gate electrode;
a second channel region of the second conductivity type provided in the second operation part;
a second transistor provided in the second operation part and comprising a gate electrode;
a gate connection electrode formed of a semiconductor and connected to the gates of the first and second transistors; and
a gate wiring formed of a metal and disposed on the gate connection electrode so as to be electrically in contact with the gate connection electrode,
wherein in plan view of the insulated gate semiconductor device the first operation part is disposed around the second operation part,
in the plan view of the insulated gate semiconductor device the gate connection electrode and the gate wiring are disposed between the first operation part and the second operation part,
the first operation part is formed in a rectangular shape, and curvatures of four corner portions of the rectangular shape are equal, and
the first and second channel regions are disposed so as to be separated from each other by a distance which allows depletion layers to come into contact with each other, the depletion layers spreading in the semiconductor layer when a reverse voltage is applied to the first and second transistors.
2. The insulated gate semiconductor device according to claim 1 , wherein the second operation part is formed in a rectangular shape, and curvatures of four corner portions of the rectangular shape are equal.
3. The insulated gate semiconductor device according to claim 1 , wherein the second transistor is a transistor for detecting a current in the first transistor.
4. The insulated gate semiconductor device according to claim 1 , wherein none of four outer peripheral lines of the rectangular shape includes a bending portion except for the four corner portions.