Semiconductor device

1. A semiconductor device, comprising:

a substrate;

a first semiconductor layer provided above the substrate, the first semiconductor layer extending in a first direction along a surface of the substrate and having a first end and a second end opposite to the first end;

a second semiconductor layer disposed between the substrate and the first semiconductor layer, the second semiconductor layer extending in the first direction and having a first end and a second end opposite to the first end;

a first conductor connected to the first end of the first semiconductor layer and the first end of the second semiconductor layer, the first conductor extending in a second direction crossing the surface of the substrate;

a second conductor extending in the second direction and including a first portion and a second portion, the first portion being connected to the second end of the first semiconductor layer and being connected to the second end of the second semiconductor layer, the second portion being positioned inside the substrate;

an electrode facing a portion between the first end and the second end of the first semiconductor layer and facing a portion between the first end and the second end of the second semiconductor layer;

a first insulating film provided between the first semiconductor layer and the electrode; and

a second insulating film provided between the second semiconductor layer and the electrode, wherein

the second conductor extends into the substrate, and

the second portion positioned inside the substrate is provided as one body with the first portion connected to the first semiconductor layer and to the second semiconductor layer.

2. The device according to claim 1 , wherein the first conductor and the second conductor extend through the first ends and the second ends of the first semiconductor layer and the second semiconductor layer.

3. The device according to claim 1 , wherein the first portion of the second conductor includes a material different from a material of the second portion of the second conductor.

4. The device according to claim 1 , wherein the first semiconductor layer and the second semiconductor layer have recesses in portions contacting the first conductor and portions contacting the second conductor.

5. The device according to claim 1 , further comprising a third insulating film provided between the substrate and the second semiconductor layer,

the electrode being provided to surround the first semiconductor layer and the second semiconductor layer in a cross section crossing the first direction,

the substrate being electrically insulated from the electrode by the third insulating film.

6. The device according to claim 5 , wherein the second conductor extends through the third insulating film and extends into the substrate.

7. The device according to claim 5 , wherein the third insulating film includes a portion positioned between the substrate and the first conductor.

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

a first interconnect connected to the first conductor; and

a second interconnect connected to the second conductor,

the first conductor and the second conductor including metal material same as materials of the first interconnect and the second interconnect.

9. The device according to claim 8 , further comprising a fourth insulating film covering the first semiconductor layer and the second semiconductor layer and being provided on the substrate,

the first interconnect and the second interconnect being provided on the fourth insulating film.

10. A semiconductor device, comprising:

a substrate;

a first semiconductor layer provided above the substrate, the first semiconductor layer extending in a first direction along a surface of the substrate and having a first end and a second end opposite to the first end;

a second semiconductor layer disposed between the substrate and the first semiconductor layer, the second semiconductor layer extending in the first direction and having a first end and a second end opposite to the first end;

a first conductor connected to the first end of the first semiconductor layer and the first end of the second semiconductor layer, the first conductor extending in a second direction crossing the surface of the substrate;

a second conductor connected to the second end of the first semiconductor layer and connected to the second end of the second semiconductor layer, the second conductor extending in the second direction;

a heat sink provided inside the substrate and connected to the second conductor;

an electrode facing a portion between the first end and the second end of the first semiconductor layer and facing a portion between the first end and the second end of the second semiconductor layer;

a first insulating film provided between the first semiconductor layer and the electrode; and

a second insulating film provided between the second semiconductor layer and the electrode.

11. The device according to claim 10 , further comprising a third insulating film provided between the substrate and the second semiconductor layer,

the electrode being provided to surround the first semiconductor layer and the second semiconductor layer in a cross section crossing the first direction,

the substrate and the heat sink being electrically insulated from the electrode by the third insulating film.

12. The device according to claim 11 , wherein

the third insulating film includes a portion positioned between the substrate and the first conductor, and

the second conductor extends through the third insulating film and is connected to the heat sink.

13. The device according to claim 10 , wherein the heat sink includes a metal material filled into the substrate.