Semiconductor memory device
View Patent ↗A semiconductor memory device comprises: a semiconductor substrate; a plurality of memory units provided on the semiconductor substrate and each including a plurality of memory cells that are stacked; and a plurality of bit lines formed above each of a plurality of the memory units aligned in a column direction, an alignment pitch in a row direction of the plurality of bit lines being less than an alignment pitch in the row direction of the memory units, and an end of each of the memory units aligned in the column direction being connected to one of the plurality of bit lines formed above the plurality of the memory units aligned in the column direction.
1. A semiconductor memory device, comprising:
a semiconductor substrate;
memory units including memory cells that are stacked above the semiconductor substrate, the memory units including a first memory unit, a second memory unit, and a third memory unit, the second memory unit being adjacent to the first memory unit in a first direction, the third memory unit being adjacent to the first memory unit in a second direction perpendicular to the first direction; and
bit lines disposed above the memory units, the bit lines extending in the second direction, the bit lines including a first bit line and a second bit line, the second bit line being adjacent to the first bit line in the first direction, wherein
a first pitch is larger than a second pitch, the first pitch being a distance between the first memory unit and the second memory unit, the second pitch being a distance between the first bit line and the second bit line.
2. The semiconductor memory device according to claim 1 , wherein
the bit lines are disposed such that the second pitch is 1/n times the first pitch (n being a natural number),
n bit lines are allocated to one column group of the memory units, and
the n bit lines are electrically connected to n memory units arranged in the second direction.
3. The semiconductor memory device according to claim 2 , wherein
one of the memory units comprises:
a semiconductor body extending in a direction perpendicular to the semiconductor substrate;
a charge storage layer surrounding the semiconductor body; and
word lines surrounding the charge storage layer.
4. The semiconductor memory device according to claim 3 , wherein
a read or write operation is performed to the memory cells in n memory units electrically connected to the n bit lines simultaneously.
5. The semiconductor memory device according to claim 4 , wherein
a width of the bit line in the first direction is smaller than a width of the semiconductor body in the first direction, and
the semiconductor body and the bit line are connected via a first bit line contact, the first bit line contact having a width smaller than a width of the semiconductor body in the first direction.
6. The semiconductor memory device according to claim 2 , further comprising:
a sense amplifier connected selectively or simultaneously to the n bit lines.
7. The semiconductor memory device according to claim 6 , wherein
a differential type sense amplifier is used as the sense amplifier.
8. The semiconductor memory device according to claim 6 , wherein
the sense amplifier is connected electrically to the first bit line among the n bit lines in which a read or write operation is performed, and the second bit line among the n bit lines other than the first bit line in which the read or write operation is performed is employed as a shield line.
9. The semiconductor memory device according to claim 1 , wherein
the memory units are electrically connected to the bit line.
10. A semiconductor memory device, comprising:
a semiconductor substrate;
memory units including memory cells that are stacked above the semiconductor substrate, the memory units being arranged with a first pitch in a row direction;
bit lines disposed above the memory units with a second pitch in the row direction, the bit lines extending in a column direction, the column direction being perpendicular to the row direction, the first pitch is larger than the second pitch; and
a bit line contact connected to one of the memory units,
the bit line contact being connected to one of the bit lines.
11. The semiconductor memory device according to claim 10 , wherein
a number of the bit lines is greater than a number of the memory units arranged in the row direction.
12. The semiconductor memory device according to claim 10 , wherein
the bit lines are disposed such that the second pitch is 1/n times the first pitch (n being a natural number),
n bit lines are allocated to one column group of the memory units, and
the n bit lines are electrically connected to n memory units arranged in the column direction.
13. The semiconductor memory device according to claim 10 , wherein
one of the memory units comprises:
a semiconductor body extending in a direction perpendicular to the semiconductor substrate;
a charge storage layer surrounding the semiconductor body; and
a word line surrounding the charge storage layer.
14. The semiconductor memory device according to claim 13 , wherein
a read or write operation is performed to the memory cells in n memory units electrically connected to the n bit lines simultaneously.
15. The semiconductor memory device according to claim 10 , wherein
the bit line contact includes a first bit line contact having a width smaller than a width of the semiconductor body in the row direction.
16. The semiconductor memory device according to claim 15 , wherein
the width of the bit lines and a width of the second bit line contact are substantively equal.
17. The semiconductor memory device according to claim 10 , wherein
a plurality of the memory units adjacent in the column direction further comprise a select gate line shared by the plurality of the memory units adjacent in the column direction.
18. A semiconductor memory device, comprising:
a semiconductor substrate;
memory units including memory cells that are stacked above the semiconductor substrate, the memory units including a first memory unit, a second memory unit, and a third memory unit, the second memory unit being adjacent to the first memory unit in a first direction, the third memory unit being adjacent to the first memory unit in a second direction perpendicular to the first direction; and
bit lines disposed above the memory units, the bit lines extending in the second direction, the bit lines including a first bit line and a second bit line, the second bit line being adjacent to the first bit line in the first direction, wherein
a number of the memory cells that are simultaneously written or read is greater than a number of the memory units aligned in the first direction.
19. The semiconductor memory device according to claim 18 , wherein
a plurality of the memory units adjacent in the column direction further comprise a select gate line shared by the plurality of the memory units adjacent in the column direction.
20. The semiconductor memory device according to claim 18 , further comprising:
a sense amplifier connected selectively or simultaneously to the bit lines.