Memory, memory operating method, and memory system
View Patent ↗A memory includes a plurality of memory cells each of which includes a memory transistor and a selection transistor; a control gate line; a selection gate line; a source line; a bit line; a first driver that sets the control gate line and the selection gate line at a first voltage in a program operation; a second driver that sets the source line at a second voltage in the program operation, and sets the source line at a third voltage higher than the second voltage while the control gate line and the selection gate line are set at the first voltage; and a third driver that sets the bit line at a fourth voltage after the source line is set at the second voltage, the bit line being coupled to a memory cell being programmed.
1. A memory comprising:
a plurality of memory cells each of which includes a memory transistor and a selection transistor coupled to the memory transistor;
a control gate line commonly coupled to gates of the memory transistors;
a selection gate line commonly coupled to gates of the selection transistors;
a source line commonly coupled to the memory cells;
a bit line coupled to each of the memory cells;
a first driver that sets the control gate line and the selection gate line at a first voltage in a program operation of the memory cell;
a second driver that sets the source line at a second voltage in the program operation, and sets the source line at a third voltage higher than the second voltage while the control gate line and the selection gate line are set at the first voltage; and
a third driver that sets the bit line at a fourth voltage after the source line is set at the second voltage, the bit line being coupled to a memory cell being programmed.
2. The memory according to claim 1 , further comprising:
a precharge circuit that is disposed between the bit line and a precharge voltage line and turns on while a common precharge signal is activated; and
a precharge control circuit that activates the common precharge signal before the source line is set at the second voltage.
3. The memory according to claim 2 , wherein the precharge circuit sets the bit line at a precharge voltage, and
wherein the precharge voltage is substantially equal to or higher than a voltage obtained by subtracting a threshold voltage of the selection transistor from the first voltage.
4. The memory according to claim 1 , further comprising:
a column switch that is disposed between the third driver and the bit line and couples the third driver to one of the bit lines in response to an address signal.
5. The memory according to claim 1 , wherein the second voltage is substantially the same as the first voltage.
6. The memory according to claim 1 , wherein the first voltage, the second voltage, and the third voltage are a voltage on a high voltage side, and
wherein the fourth voltage is a voltage on a low voltage side.
7. A memory operating method comprising:
setting, in a program operation of a memory that includes a plurality of memory cells each of which includes a memory transistor and a selection transistor coupled to the memory transistor, a control gate line commonly coupled to gates of the memory transistors, a selection gate line commonly coupled to gates of the selection transistors, a source line commonly coupled to the memory cells, and a bit line coupled to each of the memory cells, the control gate line and the selection gate line at a first voltage;
setting the source line at a second voltage;
setting the source line at a third voltage higher than the second voltage while the control gate line and the selection gate line are set at the first voltage; and
setting the bit line at a fourth voltage after the source line is set at the second voltage, wherein the bit line is coupled to a memory cell being programmed.
8. The memory operating method according to claim 7 , further comprising:
turning on a precharge circuit disposed between the bit line and a precharge voltage line before at least the source line is set at the first voltage.
9. A memory system comprising:
a memory; and
a controller that accesses the memory,
wherein the memory includes:
a plurality of memory cells each of which includes a memory transistor and a selection transistor coupled to the memory transistor;
a control gate line commonly coupled to gates of the memory transistors;
a selection gate line commonly coupled to gates of the selection transistors;
a source line commonly coupled to the memory cells;
a bit line coupled to each of the memory cells;
a first driver that sets the control gate line and the selection gate line at a first voltage in a program operation of the memory cell;
a second driver that sets the source line at a second voltage in the program operation, and sets the source line at a third voltage higher than the second voltage while the control gate line and the selection gate line are set at the first voltage; and
a third driver that sets the bit line at a fourth voltage after the source line is set at the second voltage, the bit line being coupled to a memory cell being programmed.