Semiconductor device

1. A semiconductor device comprising:

a first transistor unit including a plurality of first field effect transistors with a plurality of first gate electrodes electrically connected together, a plurality of first sources electrically connected together, and a plurality of first drains electrically connected together, the first gate electrodes being electrically connected to the first drains;

a second transistor unit including a plurality of second field effect transistors with a plurality of second gate electrodes electrically connected together, a plurality of second sources electrically connected together, and a plurality of second drains electrically connected together, the second gate electrodes being electrically connected to the first gate electrodes; and

a plurality of dummy gate electrodes electrically isolated from the first gate electrodes and the second gate electrodes,

wherein the first gate electrodes, the second gate electrodes, and the dummy gate electrodes are arranged parallel to one another, and at least one dummy gate electrode is located between any one of the first gate electrodes and any one of the second gate electrodes.

2. The semiconductor device according to claim 1 , wherein the first gate electrodes, the second gate electrodes, and the dummy gate electrodes are arranged at the same pitch.

3. The semiconductor device according to claim 1 , wherein the first gate electrodes, the second gate electrodes, and the dummy gate electrodes have the same electrode width and the same electrode length.

4. The semiconductor device according to claim 1 , wherein number of the second gate electrodes is greater than that of the first gate electrodes.

5. The semiconductor device according to claim 1 , wherein the first transistor unit and the second transistor unit are provided in the same device region.

6. The semiconductor device according to claim 5 , wherein the first gate electrodes, the second gate electrodes, and the dummy gate electrodes traverse the device region.

7. The semiconductor device according to claim 6 , wherein the device region is shaped like a polygon defined by a plurality of sides, and

at least one of the sides crosses none of the first gate electrodes, the second gate electrodes, and the dummy gate electrodes and is nonparallel to the first gate electrodes, the second gate electrodes, and the dummy gate electrodes.

8. The semiconductor device according to claim 1 , wherein a signal is input to the first transistor unit, and the second transistor unit outputs an amplified signal.

9. The semiconductor device according to claim 1 , wherein the first transistor unit and the second transistor unit make up a current mirror circuit.

10. The semiconductor device according to claim 1 , wherein the dummy gate electrodes are set at a constant potential.

11. The semiconductor device according to claim 1 , wherein at least one of the dummy gate electrodes is located between adjacent second gate electrodes.

12. The semiconductor device according to claim 1 , wherein when three consecutively arranged ones of the first and second gate electrodes are defined as a left gate electrode, a central gate electrode, and a right gate electrode,

number of dummy gate electrodes arranged between the central gate electrode and the left gate electrode is different from that of dummy gate electrodes arranged between the central gate electrode and the right gate electrode.

13. The semiconductor device according to claim 1 , wherein when a coordinate axis is defined for a direction in which the first gate electrodes, the second gate electrodes, and the dummy gate electrodes are arranged, an absolute value of sum of coordinates of the first gate electrodes is equal to that of the second gate electrodes.