Three-dimensional semiconductor memory devices

1. A three-dimensional semiconductor memory device, comprising:

an electrode structure including electrodes vertically stacked on a substrate;

first channel structures penetrating the electrode structure, each of the first channel structures including a first semiconductor pattern, a first vertical insulation layer, and a lower semiconductor pattern penetrating a lowermost one of the electrodes; and

second channel structures between the first channel structures adjacent to each other and penetrating the electrode structure, each of the second channel structures including a second semiconductor pattern penetrating the lowermost one of the electrodes, and a second vertical insulation layer,

wherein top surfaces of the second channel structures are located at a same level as top surfaces of the first channel structures,

wherein the second vertical insulation layer has a hollow pipe shape with a closed bottom end,

wherein the second vertical insulation layer has a bottom surface lower than a bottom surface of the first vertical insulation layer, and

wherein a bottom surface of second vertical insulation layer is located at a level under a top surface of the lowermost one of the electrodes.

2. The device as claimed in claim 1 , wherein the second vertical insulation layer includes a sidewall portion extended from the bottom surface to surround a sidewall of the second semiconductor pattern, and

wherein the bottom surface is located at a level between top and bottom surfaces of the lowermost one of the electrodes.

3. The device as claimed in claim 1 , wherein the second vertical insulation layer includes a sidewall portion extended from the bottom surface to surround a sidewall of the second semiconductor pattern, and

wherein the bottom surface is located at a level lower than a bottom surface of the lowermost one of the electrodes.

4. The device as claimed in claim 1 , wherein the bottom surface of the first semiconductor pattern is vertically spaced apart from a top surface of the substrate by a first distance, and

the bottom surface of the second semiconductor pattern is vertically spaced apart from the top surface of the substrate by a second distance less than the first distance.

5. The device as claimed in claim 1 , wherein the lower semiconductor pattern is between the first semiconductor pattern and the substrate,

each of the second channel structures further includes a dummy semiconductor pattern between the second semiconductor pattern and the substrate, and

a height of the lower semiconductor pattern is greater than a height of the dummy semiconductor pattern, in a vertical direction perpendicular to a top surface of the substrate.

6. The device as claimed in claim 1 , further comprising a dummy insulation pattern provided in the substrate,

wherein the bottom surface of the second vertical insulation layer is in contact with the dummy insulation pattern.

7. The device as claimed in claim 6 , wherein a portion of the second semiconductor pattern is in contact with the dummy insulation pattern.

8. The device as claimed in claim 1 , wherein each of the second channel structures further includes a dummy semiconductor pattern between the second semiconductor pattern and the substrate, and

the bottom surface of the second vertical insulation layer is between the bottom surface of the second semiconductor pattern and a top surface of the dummy semiconductor pattern.

9. The device as claimed in claim 1 , wherein the lower semiconductor pattern connects the first semiconductor pattern and the substrate.

10. The device as claimed in claim 9 , wherein the first semiconductor pattern and the first vertical insulation layer are in contact with the lower semiconductor pattern.

11. The device as claimed in claim 1 , further comprising:

contact plugs connected to the first channel structures, respectively;

a conductive line connecting adjacent two of the first channel structures,

wherein the conductive line crosses over one of the second channel structures.

12. The device as claimed in claim 1 , wherein each of the first channel structures has an upper width which is the same as an upper width of each of the second channel structures.

13. The device as claimed in claim 1 , further comprising a dummy impurity layer including first impurities in the substrate,

wherein the second channel structures are on the dummy impurity layer.

14. The device as claimed in claim 13 , wherein the bottom surface of the second vertical insulation layer is between the dummy impurity layer and the bottom surface of the second semiconductor pattern.

15. A three-dimensional semiconductor memory device, comprising:

an electrode structure including electrodes vertically stacked on a substrate;

first and second string selection electrodes horizontally spaced apart from each other on the electrode structure:

first channel structures penetrating the first and second string selection electrodes and the electrode structure, each of the first channel structures including a first semiconductor pattern, a first vertical insulation layer, and a lower semiconductor pattern penetrating a lowermost one of the electrodes; and

second channel structures disposed between the first and second string selection electrodes and penetrating the electrode structure, each of the second channel structures including a second semiconductor pattern penetrating the lowermost one of the electrodes, and a second vertical insulation layer,

wherein a portion of the second vertical insulation layer is disposed between a bottommost surface of the second semiconductor pattern and a top surface of the substrate, and

wherein a bottom surface of second vertical insulation layer is located at a level under a top surface of the lowermost one of the electrodes.

16. The device as claimed in claim 15 , wherein:

the first vertical insulation layer includes a sidewall portion surrounding a sidewall of the first semiconductor pattern and a protrusion laterally protruded from the sidewall portion, and

the first semiconductor pattern includes a stepped portion adjacent to the protrusion of the first vertical insulation layer.

17. The device as claimed in claim 15 , wherein:

the bottom surface of the first semiconductor pattern is vertically spaced apart from a top surface of the substrate by a first distance, and

the bottommost surface of the second semiconductor pattern is vertically spaced apart from the top surface of the substrate by a second distance less than the first distance.

18. The device as claimed in claim 15 , wherein an upper width of each of the first channel structures is the same as an upper width of each of the second channel structures, and a lower width each of the first channel structures is the same as a lower width of each of the second channel structures.

19. The device as claimed in claim 15 , wherein the lower semiconductor pattern is between the first semiconductor pattern and the substrate,

wherein

the first vertical insulation layer and the first semiconductor pattern are in contact with the lower semiconductor pattern.

20. The device as claimed in claim 15 , wherein:

the second vertical insulation layer includes a sidewall portion extended from the bottom surface to surround a sidewall of the second semiconductor pattern, and

the sidewall portion of the second vertical insulation layer penetrates at least a portion of the lowermost one of the electrodes.