Non-volatile semiconductor memory device in which erase and write operations are sequentially performed to control voltage thresholds of memory cells
A non-volatile semiconductor memory device includes a memory cell array and a control circuit. A control circuit performs an erase operation providing a memory cell with a first threshold voltage level for erasing data of a memory cell, and then perform a plurality of first write operations providing a memory cell with a second threshold voltage level, the second threshold voltage level being higher than the first threshold voltage level and being positive level. When the control circuit receives a first execution instruction from outside during the first write operations, the first execution instruction being for performing first function operation except for the erase operation and the first write operations, the circuit performs the first function operation during the first write operations.
1. A non-volatile semiconductor memory device comprising:
a semiconductor substrate;
a plurality of word lines stacked in a direction perpendicular to the semiconductor substrate;
a first semiconductor layer extending in the direction perpendicular to the semiconductor substrate to penetrate the word lines, and a charge accumulation layer provided between the first semiconductor layer and the word lines, the first semiconductor and the charge accumulation layer forming a plurality of memory cells to gates of which the word lines are connected, respectively; and
a control circuit configured to perform
an erase operation to bring threshold voltage levels of the memory cells below a first threshold voltage level,
first write operation to bring the threshold voltage levels of the memory cells above a second threshold voltage level, the first write operation being performed after the erase operation, the second threshold voltage level being higher than the first threshold voltage level, and
a second write operation to bring at least part of the threshold voltage levels of the memory cells above a third threshold voltage level, the second write operation being performed after the first write operation, the third threshold voltage level being higher than the second threshold voltage level,
wherein
the control circuit is further configured to
upon receipt of a suspend command during when either one of the erase operation and the first write operation is being performed, suspend the either one of the erase operation and the first write operation,
upon receipt of a first command after the either one of the erase operation and the first write operation has been suspended, perform a first operation, and
upon receipt of a resume command after the first operation has been performed, resume the either one of the erase operation and the first write operation.
2. The non-volatile semiconductor memory device according to claim 1 , wherein
the control circuit
performs the erase operation and the first write operation upon receipt of an erase command,
suspends the first write operation is being performed upon receipt of the suspend command during when the first write operation is being performed,
performs the first operation upon receipt of the first command after the first write operation has been suspended,
resumes the first write operation upon receipt of the resume command after the first operation has been performed, and
performs the second write operation upon receipt of a write command after the first write operation has been performed.
3. The non-volatile semiconductor memory device according to claim 1 , wherein
the control circuit
performs the erase operation upon receipt of an erase command,
performs the first write operation upon receipt of a first write command after the erase operation has been performed,
suspends the first write operation is being performed upon receipt of the suspend command during when the first write operation is being performed,
performs the first operation upon receipt of the first command after the first write operation has been suspended,
resumes the first write operation upon receipt of the resume command after the first operation has been performed, and
performs the second write operation upon receipt of a second write command after the first write operation has been performed.
4. The non-volatile semiconductor memory device according to claim 1 , wherein
the first operation is an operation selected from a group, the group consisting of:
a read operation;
a write operation; and
a status information output operation.
5. The non-volatile semiconductor memory device according to claim 1 , further comprising
a storage portion configured to store interruption information,
wherein
the interruption information indicates a timing at which the either one of the erase operation and the first write operation is suspended, and
the control circuit resumes the either one of the erase operation and the first write operation based on the interruption information.
6. The non-volatile semiconductor memory device according to claim 5 , wherein
the control circuit transmits the interruption information to outside upon receipt of an inquiry command.
7. The non-volatile semiconductor memory device according to claim 1 , further comprising:
a bit line; and
a source line,
wherein
the memory cell array further comprises:
a memory string including
a first select transistor connected to the bit line,
a second select transistor connected to the source line, and
the memory cells connected between the first select transistor and the second select transistor.
8. The non-volatile semiconductor memory device according to claim 7 , wherein
the memory cells includes
a plurality of series-connected first memory cells one end of which is connected to the first select transistor, and
a plurality of series-connected second memory cells one end of which is connected to the second select transistor,
a back gate transistor is provided between the other end of the first memory cells and the other end of the second memory cells.
9. The non-volatile semiconductor memory device according to claim 1 , wherein
each of the memory cells is capable of storing 2 bits or more of data after the second write operation.
10. The non-volatile semiconductor memory device according to claim 1 , wherein
each of the memory cells is capable of storing 1 bit of data after the second write operation.
11. The non-volatile semiconductor memory device according to claim 2 , wherein
the first command is a command selected from a group consisting of a read command, the write command, and a status inquiry command,
the suspend command is different from the read command, the write command, the erase command, and the status inquire command, and
the resume command is different from the read command, the write command, the erase command, the status inquire command and the suspend command.
12. A non-volatile semiconductor memory device comprising:
a semiconductor substrate;
a plurality of word lines stacked in a direction perpendicular to the semiconductor substrate;
a first semiconductor layer extending in the direction perpendicular to the semiconductor substrate, a charge accumulation layer provided between the first semiconductor layer and the word lines,
the first semiconductor layer and the charge accumulation layer forming a plurality of memory cells to gates of which the word lines are connected, respectively,
a control circuit configured to perform
upon receipt of an erase command, an erase operation to bring threshold voltage levels of the memory cells below a first threshold voltage level,
upon receipt of a first write command after the erase operation has been performed, a first write operation to bring the threshold voltage levels of the memory cells above a second threshold voltage level, the second threshold voltage level being higher than the first threshold voltage level, and
upon receipt of a second write command after the first write operation has been performed, a second write operation to bring at least part of the threshold voltage levels of the memory cells above a third threshold voltage level, the second write operation being performed after the first write operation,
wherein
the control circuit is further configured to
upon receipt of a suspend command during when the second write operation is being performed, suspend the second write operation,
upon receipt of a first command after the first write operation has been suspended, perform a first operation, and
upon receipt of a resume command after the first operation has been performed, resume the first write operation.
13. The non-volatile semiconductor memory device according to claim 12 , further comprising
a storage portion configured to store interruption information,
wherein
the interruption information indicates a timing at which the either one of the erase operation and the first write operation is suspended, and
the control circuit resumes the either one of the erase operation and the first write operation based on the interruption information.
14. The non-volatile semiconductor memory device according to claim 13 , wherein
the control circuit transmits the interruption information to outside upon receipt of an inquiry command.
15. The non-volatile semiconductor memory device according to claim 12 , further comprising:
a bit line; and
a source line,
wherein
the memory cell array further comprises:
a memory string including
a first select transistor connected to the bit line,
a second select transistor connected to the source line, and
the memory cells connected between the first select transistor and the second select transistor.
16. The non-volatile semiconductor memory device according to claim 15 , wherein
the memory cells includes
a plurality of series-connected first memory cells one end of which is connected to the first select transistor, and
a plurality of series-connected second memory cells one end of which is connected to the second select transistor,
a back gate transistor is provided between the other end of the first memory cells and the other end of the second memory cells.
17. The non-volatile semiconductor memory device according to claim 12 , wherein
each of the memory cells is capable of storing 2 bits or more of data after the second write operation.
18. The non-volatile semiconductor memory device according to claim 12 , wherein
each of the memory cells is capable of storing 1 bit of data after the second write operation.
19. The non-volatile semiconductor memory device according to claim 12 , wherein
the first command is a command selected from a group consisting of a read command, the write command, and a status inquiry command,
the suspend command is different from the read command, the write command, the erase command, and the status inquire command, and
the resume command is different from the read command, the write command, the erase command, the status inquire command and the suspend command.