Non-volatile memory device having dummy cells and memory system including the same

1. A non-volatile memory device, comprising:

a cell string comprising at least one memory cell, a ground select transistor, and at least one dummy cell between the at least one memory cell and the ground select transistor and connected to a bit line; and

a controller that executes dummy cell control logic configured to control a gate voltage of the at least one dummy cell to be lower than a threshold voltage of the at least one dummy cell in at least a part of a pre-charge period,

wherein the dummy cell control logic controls the gate voltage of the at least one dummy cell to switch between a turn on voltage and a turn off voltage of the at least one dummy cell at least once in the pre-charge period.

2. The non-volatile memory device according to claim 1 , further comprising:

a page buffer connected to the bit line,

wherein the page buffer applies a pre-charge voltage to the bit line in the pre-charge period.

3. The non-volatile memory device according to claim 1 ,

wherein the dummy cell control logic controls the gate voltage of the at least one dummy cell to be lower than the threshold voltage of the at least one dummy cell before a start of the pre-charge period.

4. The non-volatile memory device according to claim 1 ,

wherein the dummy cell control logic controls the gate voltage of the at least one dummy cell to be higher than the threshold voltage of the at least one dummy cell after an end of the pre-charge period.

5. The non-volatile memory device according to claim 1 ,

wherein select transistor control logic is configured, when executed, to control a gate voltage of the ground select transistor to be higher than a threshold voltage of the ground select transistor in the pre-charge period.

6. The non-volatile memory device according to claim 1 ,

wherein select transistor control logic is configured, when executed, to control a gate voltage of the ground select transistor to be lower than a threshold voltage of the ground select transistor in at least a part of the pre-charge period.

7. The non-volatile memory device according to claim 6 ,

wherein the select transistor control logic controls the gate voltage of the ground select transistor to be higher than the threshold voltage of the ground select transistor before an end of the pre-charge period.

8. The non-volatile memory device according to claim 1 ,

wherein the dummy cell control logic controls the gate voltage of the at least one dummy cell in order to set the threshold voltage of the at least one dummy cell.

9. The non-volatile memory device according to claim 1 , further comprising:

a substrate,

wherein the at least one memory cell, the at least one dummy cell, and the ground select transistor are respectively connected to at least one word line, at least one dummy word line, and at least one ground select line that are vertically stacked on the substrate.

10. The non-volatile memory device according to claim 1 ,

wherein the cell string is a NAND cell string.

11. A non-volatile memory device, comprising:

a memory cell array comprising a plurality of cell strings each comprising at least one dummy cell;

a page buffer connected to the memory cell array through a plurality of bit lines and pre-charging at least one of the plurality of bit lines; and

a controller that executes dummy cell control logic configured to control a gate voltage of the at least one dummy cell and to control a turn off voltage of the at least one dummy cell to be applied to a gate of the at least one dummy cell in at least a part of a pre-charge period in which the page buffer pre-charges at least one of the plurality of bit lines,

wherein the dummy cell control logic controls a gate voltage of at least one dummy cell to switch between a turn on voltage and a turn off voltage of each of the at least one dummy cell at least once in the pre-charge period in which the page buffer pre-charges the at least one of the plurality of bit lines.

12. The non-volatile memory device according to claim 11 ,

wherein each of the plurality of cell strings further comprises at least one memory cell and at least one ground select transistor, and

wherein the at least one dummy cell is disposed between the at least one memory cell and the at least one ground select transistor.

13. The non-volatile memory device according to claim 12 ,

wherein select transistor control logic is configured, when executed, to control a gate voltage of the at least one ground select transistor, and

wherein the select transistor control logic controls a turn on voltage of the at least one ground select transistor to be applied to a gate of the at least one ground select transistor in the pre-charge period in which the page buffer pre-charges the at least one of the plurality of bit lines.

14. A method for controlling a non-volatile memory device, comprising:

setting a threshold voltage of at least one dummy cell in a cell string of the non-volatile memory device;

controlling, by a controller in the non-volatile memory device, a gate voltage of the at least one dummy cell to be lower than the threshold voltage of the at least one dummy cell in at least a part of a pre-charge period by executing dummy cell control logic, and

controlling, by the controller, a gate voltage of at least one dummy cell to switch between a turn on voltage and a turn off voltage of each of the at least one dummy cell at least once in the pre-charge period,

wherein the at least one dummy cell is between at least one memory cell and a ground select transistor in the cell string, and

wherein the at least one dummy cell is connected to a bit line.

15. The method for controlling a non-volatile memory device according to claim 14 , further comprising:

applying, by a page buffer connected to the bit line, a pre-charge voltage to the bit line in the pre-charge period to isolate the cell string from a common source line.

16. The method for controlling a non-volatile memory device according to claim 14 ,

wherein the dummy cell control logic controls the gate voltage of the at least one dummy cell to be lower than the threshold voltage of the at least one dummy cell before a start of the pre-charge period, and

wherein the dummy cell control logic controls the gate voltage of the at least one dummy cell to be higher than the threshold voltage of the at least one dummy cell after an end of the pre-charge period so that a read operation can be performed.

17. The method for controlling a non-volatile memory device according to claim 14 ,

wherein the dummy cell control logic controls the gate voltage of the at least one dummy cell in order to set the threshold voltage of the at least one dummy cell.

18. The method for controlling a non-volatile memory device according to claim 14 ,

wherein the cell string is a NAND cell string, and

wherein the non-volatile memory device comprises a memory cell array that includes the cell string and a page buffer connected to the memory cell array through a plurality of bit lines and pre-charging at least one of the plurality of bit lines.