Semiconductor memory device and memory system
A semiconductor memory device includes: a first memory unit including first to fourth memory cells; a second memory unit including fifth to eighth memory cells; a first word line coupled to gates of the first and fifth memory cells; a second word line coupled to gates of the second and sixth memory cells; a third word line coupled to gates of the third and seventh memory cells; and a fourth word line coupled to gates of the fourth and eighth memory cells. In a write operation, writes to the fourth memory cell, the first memory cell, the eighth memory cell, and the fifth memory cell are executed in order.
1. A semiconductor memory device comprising:
a first memory unit including first to fourth memory cells stacked above a semiconductor substrate in order;
a second memory unit including fifth to eighth memory cells stacked above the semiconductor substrate in order;
a first word line coupled to gates of the first and fifth memory cells;
a second word line coupled to gates of the second and sixth memory cells;
a third word line coupled to gates of the third and seventh memory cells; and
a fourth word line coupled to gates of the fourth and eighth memory cells,
wherein, in a write operation, writes to the fourth memory cell, the first memory cell, the eighth memory cell, and the fifth memory cell are executed in order.
2. The device according to claim 1 , wherein
in the write operation, when the write to the fourth memory cell is executed, the second and sixth memory cells are in written states and the third and seventh memory cells are in unwritten states.
3. The device according to claim 1 further comprising:
a third memory cell unit including ninth to 14th memory cells stacked above the semiconductor substrate in order;
a fifth word line coupled to a gate of the 13th memory cell; and
a sixth word line coupled to a gate of the 14th memory cell,
wherein gates of the ninth to 12th memory cells are coupled to the first to fourth word lines, respectively, and
in the write operation, writes to the fifth memory cell and the 14th memory cell are executed in order.
4. The device according to claim 3 , wherein
writes to the 14th memory cell and the 11th memory cell are executed in order.
5. The device according to claim 1 further comprising:
a ninth memory cell included in the first memory cell unit and located below the first memory cell;
a 10th memory cell included in the second memory cell unit and located below the fifth memory cell; and
a fifth word line coupled to gates of the ninth and 10th memory cells,
wherein when the fourth memory cell is in a unwritten state, writes to the ninth memory cell, the second memory cell, the 10th memory cell, and the sixth memory cell are executed in order.
6. The device according to claim 1 further comprising:
a first bit line coupled to the first to fourth memory cells; and
a second bit line coupled to the fifth to eighth memory cells.
7. The device according to claim 1 , wherein
each of the first to eighth memory cells includes a charge storage layer to store data in a nonvolatile manner.
8. A memory system comprising:
a semiconductor memory device; and
a controller controlling a writing order in the device,
wherein the semiconductor memory device includes:
a first memory unit including first to fourth memory cells stacked above a semiconductor substrate in order;
a second memory unit including fifth to eighth memory cells stacked above the semiconductor substrate in order;
a first word line coupled to gates of the first and fifth memory cells;
a second word line coupled to gates of the second and sixth memory cells;
a third word line coupled to gates of the third and seventh memory cells; and
a fourth word line coupled to gates of the fourth and eighth memory cells, and
in a write operation, the controller orders the device to write to the fourth memory cell, the first memory cell,
the eighth memory cell, and the fifth memory cell in order.
9. The system according to claim 8 , wherein
in the write operation, when the write to the fourth memory cell is executed, the second and sixth memory cells are in written states and the third and seventh memory cells are in unwritten states.
10. The system according to claim 8 , wherein
the device further includes:
a third memory cell unit including ninth to 14th memory cells stacked above the semiconductor substrate in order;
a fifth word line coupled to a gate of the 13th memory cell; and
a sixth word line coupled to a gate of the 14th memory cell,
gates of the ninth to 12th memory cells are coupled to the first to fourth word lines, respectively, and
in the write operation, the controller orders the device to write to the fifth memory cell and the 14th memory cell in order.
11. The system according to claim 10 , wherein
writes to the 14th memory cell and the 11th memory cell are executed in order.
12. The system according to claim 8 , wherein
the device further includes:
a ninth memory cell included in the first memory cell unit and located below the first memory cell;
a 10th memory cell included in the second memory cell unit and located below the fifth memory cell; and
a fifth word line coupled to gates of the ninth and 10th memory cells, and
the controller orders the device to write to the ninth memory cell, the second memory cell, the 10th memory cell, and the sixth memory cell in order when the fourth memory cell is in a unwritten state.
13. The system according to claim 8 , wherein
the device further includes:
a first bit line coupled to the first to fourth memory cells; and
a second bit line coupled to the fifth to eighth memory cells.
14. The system according to claim 8 , wherein
each of the first to eighth memory cells includes a charge storage layer to store data in a nonvolatile manner.
15. A semiconductor memory device comprising:
a first memory unit including first to third memory cells stacked above a semiconductor substrate in order;
a second memory unit including fourth to sixth memory cells stacked above the semiconductor substrate in order;
a third memory unit including seventh to ninth memory cells stacked above the semiconductor substrate in order;
a first word line coupled to gates of the first, fourth, and seventh memory cells;
a second word line coupled to gates of the second, fifth, and eighth memory cells; and
a third word line coupled to gates of the third, sixth, and ninth memory cells,
wherein, in a write operation, writes to the seventh memory cell, the fifth memory cell, and the third memory cell are executed in order.
16. The device according to claim 15 , wherein
in the write operation, when the write to the seventh memory cell is executed, first, second, and fourth memory cells are in written states and the sixth, eighth, and ninth memory cells are in unwritten states.
17. The device according to claim 15 , wherein
in the write operation, when the seventh memory cell is in a unwritten state, writes to the fourth memory cell and the second memory cell are executed in order.
18. The device according to claim 15 , wherein
in the write operation, when the third memory cell is in a written state, writes to the eighth memory cell and the sixth memory cell are executed in order.
19. The device according to claim 15 further comprising:
a first bit line coupled to the first to third memory cells;
a second bit line coupled to the fourth to sixth memory cells; and
a third bit line coupled to the seventh to ninth memory cells.
20. The device according to claim 15 , wherein
each of the first to ninth memory cells includes a charge storage layer to store data in a nonvolatile manner.