Semiconductor device

1 . A semiconductor device, comprising:

a first electrode;

a first semiconductor region located on the first electrode, the first semiconductor region being of a first conductivity type, the first semiconductor region including

a first part, and

a second part located around the first part along a first plane perpendicular to a first direction, the first direction being from the first electrode toward the first semiconductor region;

a second semiconductor region located on the first part, the second semiconductor region being of a second conductivity type;

a third semiconductor region located on the second semiconductor region, the third semiconductor region being of the first conductivity type;

a gate electrode facing the second semiconductor region via a gate insulating layer in a second direction perpendicular to the first direction;

a fourth semiconductor region located around the second semiconductor region and the gate electrode along the first plane on the first part, the fourth semiconductor region being of the second conductivity type, a lower end of the fourth semiconductor region being positioned deeper than a lower end of the second semiconductor region;

a fifth semiconductor region positioned on the second part and located around an outer periphery of a portion of the fourth semiconductor region along the first plane, the fifth semiconductor region being of the second conductivity type;

a sixth semiconductor region located between the fifth semiconductor region and the portion of the fourth semiconductor region, the sixth semiconductor region being separated from the fourth and fifth semiconductor regions, the sixth semiconductor region being of the second conductivity type, the fourth semiconductor region being located between the gate electrode and the sixth semiconductor region;

a seventh semiconductor region positioned higher than the fifth semiconductor region and located around an outer periphery of an other portion of the fourth semiconductor region along the first plane, the seventh semiconductor region being separated from the fifth semiconductor region, the seventh semiconductor region being of the second conductivity type;

an eighth semiconductor region located between the seventh semiconductor region and the other portion of the fourth semiconductor region, the eighth semiconductor region being separated from the fourth, sixth, and seventh semiconductor regions, the eighth semiconductor region being of the second conductivity type;

a second electrode located on the second, third, and fourth semiconductor regions; and

a third electrode located on the eighth semiconductor region with an insulating layer interposed, the third electrode being separated from the second electrode and electrically connected with the gate electrode.

2 . The device according to claim 1 , wherein

the third electrode includes:

a wiring part including a portion extending in the second direction; and

a pad part, the pad part being longer in a third direction than the portion extending in the second direction, the third direction being perpendicular to the first and second directions, and

the eighth semiconductor region is positioned under the pad part and the wiring part.

3 . The device according to claim 2 , wherein

the wiring part is positioned on the second part.

4 . The device according to claim 2 , wherein

a plurality of the wiring parts is provided, and

at least a portion of the second electrode is positioned between one of the plurality of wiring parts and an other one of the plurality of wiring parts in the third direction.

5 . The device according to claim 4 , wherein

each of the plurality of wiring parts is connected to the pad part at one end, and

each of the plurality of wiring parts is separated from each other in the third direction at an other end.

6 . The device according to claim 2 , wherein

a plurality of the wiring parts is provided,

a portion of the second electrode is positioned between one of the plurality of wiring parts and an other one of the plurality of wiring parts in the third direction, and

an other portion of the second electrode is positioned on the plurality of wiring parts.

7 . The device according to claim 1 , wherein

a distance between the fourth semiconductor region and the sixth semiconductor region and a distance between the fifth semiconductor region and the sixth semiconductor region each are not less than 1 μm and not more than 5 μm.

8 . The device according to claim 1 , wherein

a distance between the fourth semiconductor region and the sixth semiconductor region is not more than a sum of a distance of a depletion layer spreading due to a built-in voltage of a p-n junction between the first semiconductor region and the fourth semiconductor region and a distance of a depletion layer spreading due to a built-in voltage of a p-n junction between the first semiconductor region and the sixth semiconductor region, and

a distance between the fifth semiconductor region and the sixth semiconductor region is not more than a sum of a distance of a depletion layer spreading due to a built-in voltage of a p-n junction between the first semiconductor region and the fifth semiconductor region and the distance of the depletion layer spreading due to the built-in voltage of the p-n junction between the first semiconductor region and the sixth semiconductor region.

9 . The device according to claim 1 , wherein

a distance between the fourth semiconductor region and the eighth semiconductor region and a distance between the seventh semiconductor region and the eighth semiconductor region each are not less than 1 μm and not more than 5 μm.

10 . The device according to claim 1 , wherein

a distance between the fourth semiconductor region and the eighth semiconductor region is not more than a sum of a distance of a depletion layer spreading due to a built-in voltage of a p-n junction between the first semiconductor region and the fourth semiconductor region and a distance of a depletion layer spreading due to a built-in voltage of a p-n junction between the first semiconductor region and the eighth semiconductor region, and

a distance between the seventh semiconductor region and the eighth semiconductor region is not more than a sum of a distance of a depletion layer spreading due to a built-in voltage of a p-n junction between the first semiconductor region and the seventh semiconductor region and the distance of the depletion layer spreading due to the built-in voltage of the p-n junction between the first semiconductor region and the eighth semiconductor region.

11 . The device according to claim 1 , further comprising:

a ninth semiconductor region located between the seventh semiconductor region and the eighth semiconductor region, the ninth semiconductor region being of the second conductivity type,

the ninth semiconductor region being separated from the seventh and eighth semiconductor regions,

a portion of the second electrode being located on the ninth semiconductor region.

12 . The device according to claim 1 , wherein

a plurality of the gate electrodes is provided on the first part.

13 . The device according to claim 1 , wherein

the first to eighth semiconductor regions include silicon carbide.

14 . The device according to claim 1 , wherein

the fifth semiconductor region is separated from the fourth semiconductor region.