Semiconductor memory device and operating method thereof

1. A semiconductor memory device comprising:

a memory cell array including a string wherein the string comprises a first dummy memory cell and a second dummy memory cell, wherein the string comprises a drain select transistor, first and second drain side dummy memory cells, a plurality of memory cells, first and second source side dummy memory cells, and a source select transistor;

a circuit configured to provide a program voltage and one or more operation voltages to the string during a program operation; and

control logic configured to control the circuit to increase a first threshold voltage of the first dummy memory cell and to increase a second threshold voltage of the second dummy memory cell, wherein the circuit turns off the first drain side dummy memory cell and the first source side dummy memory cell adjacent to the plurality of memory cells and generates a gate-induced drain leakage current after channels of the string are precharged,

wherein the first threshold voltage and a second threshold voltage increase by a hot carrier injection mechanism.

2. The semiconductor memory device of claim 1 , wherein the circuit increases threshold voltages of the second drain side dummy memory cell adjacent to the drain select transistor and the second source side dummy memory cell adjacent to the source select transistor.

3. The semiconductor memory device of claim 1 , wherein the circuit applies a pass voltage to the second drain side dummy memory cell adjacent to the drain select transistor and the second source side dummy memory cell adjacent to the source select transistor and flows a carrier by the gate-induced drain leakage current into charge storage layers of the second drain side dummy memory cell and the second source side dummy memory cell.

4. The semiconductor memory device of claim 3 , wherein the circuit applies a first operation voltage to the plurality of memory cells when the pass voltage is applied to the second drain side dummy memory cell and the second source side dummy memory cell.

5. The semiconductor memory device of claim 4 , wherein the circuit applies the pass voltage to the second drain side dummy memory cell and the second source side dummy memory cell and a second operation voltage to the first drain side dummy memory cell and the first source side dummy memory cell.

6. The semiconductor memory device of claim 5 , wherein the first operation voltage is higher than the second operation voltage and lower than the pass voltage, and

the second operation voltage is a voltage configured to turn off the first drain side dummy memory cell and the first source side dummy memory cell.

7. The semiconductor memory device of claim 4 , wherein the circuit applies an operation voltage so that the source select transistor is partially turned on when the second operation voltage is applied to the second drain side dummy memory cell and the second source side dummy memory cell.

8. The semiconductor memory device of claim 1 , wherein the control logic controls circuits and performs a program operation of memory cells included in the string after the threshold voltages of the plurality of dummy memory cells increase.

9. A semiconductor memory device comprising:

a memory cell array including a string comprising a drain select transistor, a plurality of drain side dummy memory cells, a plurality of memory cells, a plurality of source side dummy memory cells, and a source select transistor; and

a circuit that applies an operation voltage to the string to increase a first threshold voltage and a second threshold voltage of one or more of the plurality of drain side dummy memory cells and one or more of the plurality of source side dummy memory cells, and programs a selected memory cell from among the plurality of memory cells,

wherein the circuit applies the operation voltage to turn off a first drain side dummy memory cell and a first source side dummy memory cell adjacent to the plurality of memory cells and generates a gate-induced drain leakage current.

10. The semiconductor memory device of claim 9 , wherein the circuit increases the threshold voltages of one or more of the plurality of drain side dummy memory cells and one or more of the plurality of source side dummy memory cells by a hot carrier injection mechanism.

11. The semiconductor memory device of claim 9 , wherein the circuit applies a pass voltage to a second drain side dummy memory cell adjacent to the drain select transistor and a second source side dummy memory cell adjacent to the source select transistor and flows a carrier by the gate-induced drain leakage into charge storage layers of the second drain side dummy memory cell and the second source side dummy memory cell.

12. The semiconductor memory device of claim 9 , wherein the circuit applies the operation voltage to the first drain side dummy memory cell and the first source side dummy memory cell before a program voltage is applied to the selected memory cell.

13. The semiconductor memory device of claim 9 , wherein the circuit applies a turn-on voltage to the drain select transistor and the source select transistor when the operation voltage is applied to the first drain side dummy memory cell and the first source side dummy memory cell.

14. A method comprising:

precharging channels of a string, wherein the string comprises a drain select transistor, a source select transistor, a first drain side dummy memory cell, a second drain side dummy memory cell, a first source side dummy memory cell, a second source side dummy memory cell, and a plurality of memory cells,

wherein a semiconductor memory device comprises the string;

applying a turn-off voltage to the first drain side dummy memory cell and the first source side dummy memory cell;

generating a gate-induced drain leakage;

applying a pass voltage to the second drain side dummy memory cell while the first drain side dummy memory cell is in a turn-off state and to the second source side dummy memory cell while the first source side dummy memory cell is in the turn-off state;

increasing threshold voltages of the second drain side dummy memory cell and the second source side dummy memory cell; and

applying a program voltage to a selected memory cell from among the plurality of memory cells.

15. The operating method of claim 14 , wherein a voltage lower than the pass voltage is applied to the plurality of memory cells when the pass voltage is applied.

16. The operating method of claim 14 , wherein a turn-on voltage is applied to the drain select transistor and the source select transistor when the turn-off voltage is applied to the first drain side dummy memory cell and the first source side dummy memory cell.

17. The operating method of claim 14 , wherein the increasing of the threshold voltages of the second drain side dummy memory cell and the second source side dummy memory cell is performed by a hot carrier injection mechanism.