Double-source semiconductor device

1. A semiconductor device, comprising:

a first source layer;

a first insulating layer located over the first source layer;

a first stacked structure located over the first insulating layer;

first channel layers passing through the first stacked structure and the first insulating layer; and

a second source layer including a first region interposed between the first source layer and the first insulating layer and a second region interposed between the first channel layers and the first insulating layer.

2. The semiconductor device of claim 1 , further comprising a memory layer interposed between the first channel layers and the first stacked structure.

3. The semiconductor device of claim 1 , wherein the first stacked structure includes second insulating layers and gate electrodes stacked alternately with each other.

4. The semiconductor device of claim 1 , further comprising:

a first slit insulating layer passing through a lower portion of the first stacked structure, extending in substantially one direction, and located in a contact region; and

a second slit insulating layer passing through the first stacked structure, coupled to the first slit insulating layer to extend in substantially the one direction, and located in a cell region.

5. The semiconductor device of claim 1 , further comprising:

a third insulating layer passing through the first source layer and the first insulating layer and located in a contact region; and

a third slit insulating layer passing through the first stacked structure and located over the third insulating layer.

6. The semiconductor device of claim 1 , further comprising:

a second stacked structure located over the first stacked structure;

second channel layers passing through the second stacked structure; and

a coupling pattern surrounding lower portions of the second channel layers and coupling the first channel layers and the second channel layers to each other.

7. The semiconductor device of claim 1 , wherein the first source layer is a region doped with impurities in a substrate.

8. The semiconductor device of claim 1 , wherein the first region of the second source layer directly contacts the first source layer, and the second region of the second source layer directly contacts the first channel layers.

9. The semiconductor device of claim 1 , wherein the second source layer includes a silicon layer or a silicide layer.

10. The semiconductor device of claim 1 , wherein the second region of the second source layer directly contacts the first channel layers and has a substantially uniform height.

11. The semiconductor device of claim 1 , wherein the first region of the second source layer directly contacts the first source layer and has a substantially uniform height.

12. The semiconductor device of claim 1 , wherein the first region of the second source layer directly contacts the second region of the second source layer.

13. A semiconductor device, comprising:

a first source layer;

a first insulating layer formed over the first source layer;

a first stacked structure formed over the first insulating layer;

first channel layers passing through the first stacked structure;

gap-filling insulating layers formed in the first channel layers and passing through the first insulating layer; and

a second source layer including a first region interposed between the gap-filling insulating layers and the first insulating layer.

14. The semiconductor device of claim 13 , wherein the second source layer includes a second region interposed between the first source layer and the first insulating layer.

15. The semiconductor device of claim 13 , wherein the first region of the second source layer directly contacts the first source layer and the first channel layers.

16. The semiconductor device of claim 13 , wherein the second source layer includes a silicide layer.