Semiconductor memory device
According to one embodiment, a semiconductor memory device includes a first memory cell array including a first block that includes memory cells, a second memory cell array including a second block that includes memory cells, word lines arranged in the first and second memory cell arrays, and a row decoder including transfer gates that respectively transfer voltages to the word lines. Word lines arranged in the first block include first and second groups, word lines arranged in the second block include third and fourth groups, and the first and third groups commonly use the transfer gates.
1. A semiconductor memory device comprising:
a first memory cell array comprising a first block that comprises memory cells;
a second memory cell array comprising a second block that comprises memory cells;
word lines arranged in the first and second memory cell arrays; and transfer gates configured to transfer voltages to the word lines;
wherein:
word lines arranged in the first block comprise first and second groups,
word lines arranged in the second block comprise third and fourth groups,
the transfer gates comprise first transfer gates, second transfer gates, and third transfer gates,
the first and third groups commonly use the first transfer gates,
the second transfer gates are connected to the second group and are not connected to the fourth group,
the third transfer gates are connected to the fourth group and are not connected to the second group;
the word lines in the first block are connected to the first memory cells,
the first memory cells are serially connected,
the word lines in the second block are connected to second memory cells, and
the second memory cells are serially connected.
2. The device of claim 1 , wherein:
the first transfer gates are arranged between the first and second memory cell arrays,
the second transfer gates are arranged on a side opposite to the first transfer gates with respect to the first memory cell array, and
the third transfer gates are arranged on a side opposite to the first transfer gates with respect to the second memory cell array.
3. The device of claim 1 , further comprising
a decoding circuit configured to simultaneously select the transfer gates connected to the first and second blocks.
4. The device of claim 2 , further comprising
a driver configured to apply voltages of the word lines to the transfer gates according to an operation mode, wherein the driver supplies the same signal to gate electrodes of the first to third transfer gates.
5. The device of claim 1 , further comprising:
a first bit line connected to the first block;
a second bit line connected to the second block; and
a control circuit configured to apply an erase voltage to a first well in which the first block is formed when data is erased from the first block, wherein the control circuit applies a ground voltage to a second well in which the second block is formed when data is erased from the first block.
6. The device of claim 5 , wherein the control circuit applies a first voltage to the first bit line and applies a second voltage that is higher than the first voltage to the second bit line when data is erased from the first block.
7. The device of claim 1 , further comprising:
a first bit line connected to the first block;
a second bit line connected to the second block; and
a control circuit configured to sense a voltage of the first bit line when data is read from the first block, wherein the control circuit applies a ground voltage to the second bit line when data is read from the first block.
8. The device of claim 7 , further comprising:
a first sense amplifier connected to the first bit line; and
a second sense amplifier connected to the second bit line, wherein the second sense amplifier is deactivated when data is read from the first block.
9. The device of claim 1 , further comprising:
a first bit line connected to the first block;
a second bit line connected to the second block; and
a control circuit configured to apply one of a ground voltage and power source voltage to the first bit line according to data when data is written to the first block, wherein the control circuit applies the power source voltage to the second bit line to set the second block in a write inhibition state when data is written to the first block.
10. The device of claim 9 , wherein the control circuit applies the ground voltage to the first bit line when data is written to the first block.
11. The device of claim 1 , wherein:
the first memory cell array comprises first blocks, and
the second memory cell array comprises second blocks.
12. The device of claim 11 , further comprising
a decoding circuit configured to simultaneously select transfer gates connected to a pair of first and second blocks.
13. The device of claim 12 , wherein the decoding circuits are alternately arranged on both sides of the first and second memory cell arrays.
14. The device of claim 1 , wherein each of the first and second memory cell arrays is a NAND flash memory.
15. The device of claim 1 that is a non-volatile semiconductor memory device.
16. The device of claim 1 that is a non-volatile semiconductor memory device that comprises a plurality of memory cell arrays, wherein the memory cell arrays comprise a plurality of memory cells arranged in matrix form and includes a rewritable EEPROM (“Electrically Erasable Programmable Read-Only Memory”) cell.