Non-volatile semiconductor storage device and method of manufacturing the same
A non-volatile semiconductor storage device has a plurality of memory strings to each of which a plurality of electrically rewritable memory cells are connected in series. Each of the memory strings includes first semiconductor layers each having a pair of columnar portions extending in a vertical direction with respect to a substrate and a coupling portion formed to couple the lower ends of the pair of columnar portions; a charge storage layer formed to surround the side surfaces of the columnar portions; and first conductive layers formed to surround the side surfaces of the columnar portions and the charge storage layer. The first conductive layers function as gate electrodes of the memory cells.
1. A nonvolatile semiconductor memory device, comprising:
a substrate;
a first memory string including a first substring, a second substring and a first coupling transistor coupling the first substring and the second substring, each of the first substring and the second substring including a plurality of first memory cell transistors connected in series, each of the first substring and the second substring extending in a first direction crossing the substrate; and
a second memory string including a third substring, a fourth substring and a second coupling transistor coupling the third substring and the fourth substring, each of the third substring and the fourth substring including a plurality of second memory cell transistors connected in series, each of the third substring and the fourth substring extending in the first direction,
wherein, in a read operation, data is not read from the first coupling transistor,
the first coupling transistor and the second coupling transistor share a gate line extending in two dimensions crossing the first direction,
the first substring and the third substring share a first set of word lines, and
the second substring and the fourth substring share a second set of word lines.
2. The semiconductor memory device according to claim 1 , wherein
one of the plurality of first memory cell transistors includes an insulating portion, a first semiconductor layer, a first gate insulating layer including a charge accumulation layer, and one of the first set of word lines, the first semiconductor layer being disposed between the insulating portion and the first gate insulating layer, the first gate insulating layer being disposed between the first semiconductor layer and the one of the first set of word lines.
3. The semiconductor memory device according to claim 2 , wherein the first coupling transistor includes a second gate insulating layer, a layer structure of the second gate insulating layer being the same as a layer structure of the first gate insulating layer.
4. The semiconductor memory device according to claim 1 , wherein, at a first reading timing in a read operation,
a first reading voltage is applied to one of the first set of word lines and the second set of word lines,
a second reading voltage is applied to other word lines among the first set of word lines and the second set of word lines, the first reading voltage being smaller than the second reading voltage, and
a third reading voltage is applied to the gate line of the first coupling transistor and the second coupling transistor.
5. The semiconductor memory device according to claim 4 , wherein the second reading voltage is different from the third reading voltage.
6. The semiconductor memory device according to claim 4 , wherein, at a second programming timing in a write operation,
a fourth programming voltage is applied to one of the first set of word lines and the second set of word lines,
a fifth programming voltage is applied to other word lines among the first set of word lines and the second set of word lines, the fourth programming voltage being larger than the fifth programming voltage, and
the third reading voltage is applied to the gate line of the first coupling transistor and the second coupling transistor.
7. The semiconductor memory device according to claim 6 , wherein, at a second erasing timing in an erase operation,
a third erasing voltage is applied to the first set of word lines and the second set of word lines, and
the third reading voltage is applied to the gate line of the first coupling transistor and the second coupling transistor.
8. The semiconductor memory device according to claim 1 , wherein, in a write operation, data is written to one of the plurality of first memory cell transistors.
9. The semiconductor memory device according to claim 8 , wherein data is not written to the first coupling transistor.
10. The semiconductor memory device according to claim 1 , wherein, at a first programming timing in a write operation,
a first programming voltage is applied to one of the first set of word lines and the second set of word lines,
a second programming voltage is applied to other word lines among the first set of word lines and the second set of word lines, the first programming voltage being larger than the second programming voltage, and
a third programming voltage is applied to the gate line of the first coupling transistor and the second coupling transistor.
11. The semiconductor memory device according to claim 10 , wherein the second programming voltage is different form the third programming voltage.
12. The semiconductor memory device according to claim 1 , wherein in an erase operation, data is erased from the plurality of first memory cell transistors.
13. The semiconductor memory device according to claim 12 , wherein data is not erased from the first coupling transistor.
14. The semiconductor memory device according to claim 1 , wherein, at a first erasing timing in an erase operation,
a first erasing voltage is applied to the first set of word lines and the second set of word lines, and
a second erasing voltage is applied to the gate line of the first coupling transistor and the second coupling transistor.
15. The semiconductor memory device according to claim 14 , wherein the first erasing voltage is different from the second erasing voltage.
16. The semiconductor memory device according to claim 1 , wherein a first number of the first memory cell transistors in the first substring is the same as a second number of the first memory cell transistors in the second substring.
17. The semiconductor memory device according to claim 1 , wherein the first set of the word lines extends in a second direction crossing the first direction, and is formed in a staircase shape in a contact region.
18. The semiconductor memory device according to claim 1 , further comprising:
a bit line; and
a first select gate transistor disposed between the bit line and the first substring.
19. The semiconductor memory device according to claim 18 , further comprising:
a source line; and
a second select gate transistor disposed between the source line and the second substring.
20. The semiconductor memory device according to claim 19 , wherein the source line is disposed above the substrate through an insulating material.
21. The semiconductor memory device according to claim 19 , wherein the first set of word lines are disposed between the bit line and the substrate, and the source line is disposed between the bit line and the substrate.
22. The semiconductor memory device according to claim 19 , wherein the second set of word lines are disposed between the source line and the substrate.
23. The semiconductor memory device according to claim 1 , further comprising:
a first transistor disposed on the substrate, the first transistor including side walls and a channel region extending in a lateral direction of the substrate.
24. The semiconductor memory device according to claim 23 , further comprising:
a second transistor disposed on the substrate, a dimension of the first transistor being different from a dimension of the second transistor.
25. The semiconductor memory device according to claim 23 , further comprising:
an uppermost wiring, the first transistor including a first gate electrode coupled to the uppermost wiring through a plurality of first wirings and a plurality of plug conductors, wherein a first pair of one of the plurality of first wirings and one of the plurality of plug conductors is stacked on a second pair of one of the plurality of first wirings and one of the plurality of plug conductors.
26. The semiconductor memory device according to claim 25 , wherein the first pair is formed as a configuration of dual damascene.
27. A nonvolatile semiconductor memory device, comprising:
a first memory string including a first substring, a second substring and a first coupling transistor coupling the first substring and the second substring, each of the first substring and the second substring including a plurality of first memory cell transistors connected in series, each of the first substring and the second substring extending in a first direction;
a second memory string including a third substring, a fourth substring and a second coupling transistor coupling the third substring and the fourth substring, each of the third substring and the fourth substring including a plurality of second memory cell transistors connected in series, each of the third substring and the fourth substring extending in the first direction, the first memory string and the second memory string being arranged in a second direction crossing the first direction; and
a third memory string including a fifth substring, a sixth substring and a third coupling transistor coupling the fifth substring and the sixth substring, each of the fifth substring and the sixth substring including a plurality of third memory cell transistors connected in series, each of the fifth substring and the sixth substring extending in the first direction, the first memory string and the third memory string being arranged in a third direction crossing the first direction and the second direction,
wherein, in a read operation, data is not read from the first coupling transistor,
the first coupling transistor, the second coupling transistor and the third coupling transistor share a gate line extends in two dimensions crossing the first direction,
the first substring, the third substring and the fifth substring share a first set of word lines, and
the second substring, the fourth substring and the sixth substring share a second set of word lines.
28. The semiconductor memory device according to claim 27 , wherein
one of the plurality of first memory cell transistors includes an insulating portion, a first semiconductor layer, a first gate insulating layer including a charge accumulation layer, and one of the first set of word lines, the first semiconductor layer being disposed between the insulating portion and the first gate insulating layer, the first gate insulating layer being disposed between the first semiconductor layer and the one of the first set of word lines.
29. The semiconductor memory device according to claim 28 , wherein the first coupling transistor includes a second gate insulating layer, a layer structure of the second gate insulating layer being the same as a layer structure of the first gate insulating layer.
30. The semiconductor memory device according to claim 27 , wherein, at a first reading timing in a read operation,
a first reading voltage is applied to one of the first set of word lines and the second set of word lines,
a second reading voltage is applied to other word lines among the first set of word lines and the second set of word lines, the first reading voltage being smaller than the second reading voltage, and
a third reading voltage is applied to the gate line of the first coupling transistor, the second coupling transistor and the third coupling transistor.
31. The semiconductor memory device according to claim 30 , wherein the second reading voltage is different from the third reading voltage.
32. The semiconductor memory device according to claim 30 , wherein, at a second programming timing in a write operation,
a fourth programming voltage is applied to one of the first set of word lines and the second set of word lines,
a fifth programming voltage is applied to other word lines among the first set of word lines and the second set of word lines, the fourth programming voltage being larger than the fifth programming voltage, and
the third reading voltage is applied to the gate line of the first coupling transistor, the second coupling transistor and the third coupling transistor.
33. The semiconductor memory device according to claim 32 , wherein, at a second erasing timing in an erase operation,
a third erasing voltage is applied to the first set of word lines and the second set of word lines, and
the third reading voltage is applied to the gate line of the first coupling transistor, the second coupling transistor and the third coupling transistor.
34. The semiconductor memory device according to claim 27 , wherein, in a write operation, data is written to one of the plurality of first memory cell transistors.
35. The semiconductor memory device according to claim 34 , wherein data is not written to the first coupling transistor.
36. The semiconductor memory device according to claim 27 , wherein, at a first programming timing in a write operation,
a first programming voltage is applied to one of the first set of word lines and the second set of word lines,
a second programming voltage is applied to other word lines among the first set of word lines and the second set of word lines, the first programming voltage being larger than the second programming voltage, and
a third programming voltage is applied to the gate line of the first coupling transistor, the second coupling transistor and the third coupling transistor.
37. The semiconductor memory device according to claim 36 , wherein the second programming voltage is different form the third programming voltage.
38. The semiconductor memory device according to claim 27 , wherein in an erase operation, data is erased from the plurality of first memory cell transistors.
39. The semiconductor memory device according to claim 38 , wherein data is not erased from the first coupling transistor.
40. The semiconductor memory device according to claim 27 , wherein, at a first erasing timing in an erase operation,
a first erasing voltage is applied to the first set of word lines and the second set of word lines, and
a second erasing voltage is applied to the gate line of the first coupling transistor, the second coupling transistor and the third coupling transistor.
41. The semiconductor memory device according to claim 40 , wherein the first erasing voltage is different from the second erasing voltage.
42. The semiconductor memory device according to claim 27 , wherein a first number of the first memory cell transistors in the first substring is the same as a second number of the first memory cell transistors in the second substring.
43. The semiconductor memory device according to claim 27 , wherein the first set of the word lines extends in the second direction, and is formed in a staircase shape in a contact region.
44. The semiconductor memory device according to claim 27 , further comprising:
a bit line, and
a first select gate transistor disposed between the bit line and the first substring.
45. The semiconductor memory device according to claim 44 , further comprising:
a source line; and
a second select gate transistor disposed between the source line and the second substring.
46. The semiconductor memory device according to claim 27 , further comprising:
a substrate; and
a first transistor disposed on the substrate, the first transistor including side walls and a channel region extending in a lateral direction of the substrate.
47. The semiconductor memory device according to claim 46 , further comprising:
a second transistor disposed on the substrate, a dimension of the first transistor being different from a dimension of the second transistor.
48. The semiconductor memory device according to claim 46 , further comprising:
an uppermost wiring, the first transistor including a first gate electrode coupled to the uppermost wiring through a plurality of first wirings and a plurality of plug conductors, wherein a first pair of one of the plurality of first wirings and one of the plurality of plug conductors is stacked on a second pair of one of the plurality of first wirings and one of the plurality of plug conductors.
49. The semiconductor memory device according to claim 48 , wherein the first pair is formed as a configuration of dual damascene.