The applying may include applying a GND voltage to the source electrode, applying a positive voltage (VPP) to the control gate electrode, and applying a positive voltage that is smaller than that of the control gate electrode to the drain electrode.

The repetitively performing may include comparing a number of times that the applying is performed with a fourth setting value, terminating the program by determining as the program failure in response to the number of times being is greater than the fourth setting value as a result of the comparison, and performing the applying, measuring, and determining in response to the number of times being smaller than or equal to the fourth setting value as a result of the comparison.

The measuring may include applying a GND voltage to the source electrode, and applying a low voltage for causing the electrons injected into a floating gate not to exit the floating gate to the drain electrode and the control gate electrode.

The drain electrode may be applied with a first voltage that is greater than a GND voltage, and the control gate electrode is applied with a second voltage that is greater than the first voltage.

Other features and aspects will be apparent from the following detailed description, the drawings, and the claims.