Memory device and program operation thereof

1. A memory device, comprising:

a memory string comprising a drain select gate (DSG) transistor, a plurality of memory cells, and a source select gate (SSG) transistor; and

a peripheral circuit coupled to the memory string and configured to:

in response to an interrupt during a program operation on a select memory cell of the plurality of memory cells, turn on at least one of the DSG transistor or the SSG transistor; and

suspend the program operation after turning on the at least one of the DSG transistor or the SSG transistor.

2. The memory device of claim 1 , wherein the peripheral circuit is further configured to turn on the select memory cell, and an unselect memory cell of the plurality of memory cells while turning on the at least one of the DSG transistor or the SSG transistor, the unselect memory cell being between the select memory cell and the at least one of the DSG transistor or the SSG transistor.

3. The memory device of claim 1 , wherein at least one of a drain or a source of the memory string is grounded when the at least one of the DSG transistor or the SSG transistor is turned on.

4. The memory device of claim 1 , wherein the peripheral circuit is further configured to, in response to completion of another operation triggered by the interrupt, resume the program operation.

5. The memory device of claim 4 , wherein the another operation comprises a read operation.

6. The memory device of claim 1 , wherein the peripheral circuit is configured to turn on the SSG transistor.

7. The memory device of claim 6 , further comprising:

a select word line coupled to the select memory cell; and

an SSG line coupled to the SSG transistor,

wherein the peripheral circuit comprises a word line driver configured to:

apply a program voltage on the select word line to program the select memory cell; and

apply an SSG voltage on the SSG line to turn on the SSG transistor after applying the program voltage on the select word line.

8. The memory device of claim 7 , further comprising an unselect word line coupled to an unselect memory cell of the plurality of memory cells,

wherein the word line driver is further configured to apply a pass voltage on the unselect word line to turn on the unselect memory cell while applying the program voltage on the select word line and while applying the SSG voltage on the SSG line.

9. The memory device of claim 7 , wherein the word line driver is further configured to:

discharge the program voltage on the select word line;

apply a pass voltage on the select word line to turn on the select memory cell after discharging the program voltage on the select word line; and

apply the SSG voltage on the SSG line while applying the pass voltage on the select word line.

10. The memory device of claim 7 , wherein the word line driver is further configured to:

discharge the program voltage on the select word line; and

apply the SSG voltage on the SSG line while discharging the program voltage on the select word line.

11. The memory device of claim 10 , wherein the word line driver is further configured to apply the SSG voltage when the discharged program voltage still turns on the select memory cell.

12. The memory device of claim 7 , wherein the interrupt occurs while applying the program voltage on the select word line.

13. A system, comprising:

a memory device configured to store data and comprising:

a memory string comprising a drain select gate (DSG) transistor, a plurality of memory cells, and a source select gate (SSG) transistor; and

a peripheral circuit coupled to the memory string and configured to:

initiate a program operation on a select memory cell of the plurality of memory cells;

receive an interrupt command during the program operation;

in response to receiving the interrupt command, turn on at least one of the DSG transistor or the SSG transistor; and

suspend the program operation after turning on the at least one of the DSG transistor or the SSG transistor;

a memory controller coupled to the memory device and configured:

transmit a program command to the peripheral circuit to initiate the program operation; and

transmit the interrupt command after the program command to the peripheral circuit; and

a connector configured to couple the system to a host.

14. A method for operating a memory device comprising a memory string, the memory string comprising a drain select gate (DSG) transistor, a plurality of memory cells, and a source select gate (SSG) transistor, the method comprising:

initiating a program operation on a select memory cell of the plurality of memory cells;

receiving an interrupt command during the program operation;

in response to receiving the interrupt command, turning on at least one of the DSG transistor or the SSG transistor; and

suspending the program operation after turning on the at least one of the DSG transistor or the SSG transistor.

15. The method of claim 14 , further comprising turning on the select memory cell and an unselect memory cell of the plurality of memory cells while turning on the at least one of the DSG transistor or the SSG transistor, the unselect memory cell being between the select memory cell and the at least one of the DSG transistor or the SSG transistor.

16. The method of claim 14 , wherein at least one of a drain or a source of the memory string is grounded when the at least one of the DSG transistor or the SSG transistor is turned on.

17. The method of claim 14 , wherein turning on the at least one of the DSG transistor or the SSG transistor comprises turning on the DSG transistor.

18. The method of claim 17 , further comprising:

applying a program voltage on a select word line coupled to the select memory cell to program the select memory cell; and

applying an SSG voltage on an SSG line coupled to the SSG transistor to turn on the SSG transistor after applying the program voltage on the select word line.

19. The method of claim 18 , further comprising:

discharging the program voltage on the select word line;

applying a pass voltage on the select word line to turn on the select memory cell after discharging the program voltage on the select word line; and

applying the SSG voltage on the SSG line while applying the pass voltage on the select word line.

20. The method of claim 18 , further comprising:

discharging the program voltage on the select word line; and

applying the SSG voltage on the SSG line while discharging the program voltage on the select word line.