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 non-volatile semiconductor storage device comprising:
a substrate;
a first semiconductor layer extending in a first direction, the first direction crossing a surface of a substrate;
a second semiconductor layer extending in the first direction;
a third semiconductor layer extending in a second direction above the substrate, the second direction crossing the first direction, the third semiconductor layer being connected to a lower part of the first semiconductor layer and a lower part of the second semiconductor layer;
a first electrode layer disposed above the substrate and extending in a third direction, the third direction crossing the first direction and the second direction;
a first memory portion disposed between the first semiconductor layer and the first electrode layer;
a second electrode layer disposed above the first electrode layer and extending in the third direction;
a second memory portion disposed between the first semiconductor layer and the second electrode layer; and
a first bit line electrically connected with the first semiconductor layer, the first bit line extending in the second direction; and
a source line electrically connected with the second semiconductor layer, the source line extending in the third direction.
2. The device according to claim 1 , wherein a distance between the first bit line and the substrate is larger than a distance between the source line and the substrate.
3. The device according to claim 1 , further comprising
a third electrode layer disposed above the substrate and extending in the third direction; and
a third memory portion disposed between the second semiconductor layer and the third electrode layer.
4. The device according to claim 1 , further comprising
a fourth semiconductor layer extending in the first direction, the source line being electrically connected with the fourth semiconductor layer;
a fifth semiconductor layer extending in the first direction, the first to the fourth semiconductor layer being arranged in the second direction, the first bit line being electrically connected with the fifth semiconductor layer; and
a sixth semiconductor layer extending in the second direction above the substrate, the sixth semiconductor layer being connected to a lower part of the fourth semiconductor layer and a lower part of the fifth semiconductor layer.
5. The device according to claim 4 , further comprising
a fourth electrode layer disposed above the substrate and extending in the third direction, the fourth electrode layer being electrically connected with the first electrode layer; and
a fourth memory portion disposed between the fifth semiconductor layer and the fourth electrode layer.
6. The device according to claim 5 , further comprising
a third electrode layer disposed above the substrate and extending in the third direction;
a third memory portion disposed between the second semiconductor layer and the third electrode layer; and
a fifth memory portion disposed between the fourth semiconductor layer and the third electrode layer.
7. The device according to claim 1 , further comprising
a seventh semiconductor layer extending in the first direction, the first semiconductor layer and the seventh semiconductor layer being arranged in the third direction;
a eighth semiconductor layer extending in the first direction, the second semiconductor layer and the eighth semiconductor layer being arranged in the third direction, the source line being electrically connected with the eighth semiconductor layer; and
a ninth semiconductor layer extending in the second direction above the substrate, the ninth semiconductor layer being connected to a lower part of the seventh semiconductor layer and a lower part of the eighth semiconductor layer; and
a second bit line electrically connected with the seventh semiconductor layer, the second bit line having a longitudinal direction in the second direction.
8. The device according to claim 1 , further comprising
a tenth semiconductor layer extending in the first direction, the tenth semiconductor layer being formed apart in both the second direction and the third direction from the first semiconductor layer, the source line being electrically connected with the tenth semiconductor layer;
an eleventh semiconductor layer extending in the first direction, the tenth semiconductor layer and the eleventh semiconductor layer being arranged in the second direction; and
a twelfth semiconductor layer extending in the second direction above the substrate, the twelfth semiconductor layer being connected to a lower part of the tenth semiconductor layer and a lower part of the eleventh semiconductor layer; and
a third bit line electrically connected with the eleventh semiconductor layer, the first bit line and the third bit line being arranged adjacent to each other in the third direction.
9. The device according to claim 8 , further comprising a fifth electrode layer disposed above the substrate and extending in the third direction, the fifth electrode layer being electrically connected with the first electrode layer; and
a sixth memory portion disposed between the eleventh semiconductor layer and the fifth electrode layer.
10. The device according to claim 9 , further comprising
a third electrode layer disposed above the substrate and extending in the third direction;
a third memory portion disposed between the second semiconductor layer and the third electrode layer; and
a seventh memory portion disposed between the tenth semiconductor layer and the third electrode layer.
11. A non-volatile semiconductor storage device having:
a substrate;
a first bit line extending in a first direction;
a source line extending in a second direction, the second direction crossing the first direction; and
a first memory string having a first memory cell and a second memory cell connected in series, a distance between the first memory cell and the substrate being larger than a distance between the second memory cell and the substrate, a first end of the first memory string being connected with the first bit line, a second end of the first memory string being connected with the source line, a distance between the first bit line and the substrate being larger than a distance between the source line and the substrate.
12. The device according to claim 11 , wherein the first memory string has a third memory cell connected in series with the first memory cell and the second memory cell, the third memory cell being formed apart in the first direction from the first memory cell.
13. The device according to claim 11 , further comprising
a second memory string formed apart in the first direction from the first memory string, a first end of the second memory string being connected with the first bit line, a second end of the second memory string being connected with the source line.
14. The device according to claim 13 , wherein the second memory string has a fourth memory cell, a gate of the fourth memory cell being electrically connected with a gate of the first memory cell.
15. The device according to claim 14 , wherein
the second memory string has a fifth memory cell connected in series with the fourth memory cell, the fifth memory cell being formed apart in the first direction from the fourth memory cell,
wherein the first memory string has a third memory cell connected in series with the first memory cell and the second memory cell, the third memory cell being formed apart in the first direction from the first memory cell, a gate of the third memory cell being electrically connected with a gate of the fifth memory cell.
16. The device according to claim 11 , further comprising
a second bit line extending in the first direction; and
a third memory string formed apart in the second direction from the first memory string, a first end of the third memory string being connected with the second bit line, a second end of the third memory string being connected with the source line.
17. The device according to claim 11 , further comprising
a third bit line extending in the first direction, the first bit line and the third bit line being arranged adjacent to each other in the second direction
a fourth memory string formed apart in both the first direction and the second direction from the first memory string, a first end of the fourth memory string being connected with the third bit line, a second end of the fourth memory string being connected with the source line.
18. The device according to claim 11 , further comprising
a fourth memory string having a sixth memory cell, a gate of the sixth memory cell being electrically connected with a gate of the first memory cell.
19. The device according to claim 18 , wherein
the fourth memory string has a seventh memory cell connected in series with the sixth memory cell, the seventh memory cell being formed apart in the first direction from the sixth memory cell,
wherein the first memory string has a third memory cell connected in series with the first memory cell and the second memory cell, the third memory cell being formed apart in the first direction from the first memory cell, a gate of the third memory cell being electrically connected with a gate of the seventh memory cell.