SEMICONDUCTOR FLASH MEMORY DEVICE AND THE METHOD FOR OPERATING THE SAME

A semiconductor flash memory device and a method for driving the same are provided to improve programming disturbance of adjacent transistors in a unit cell by reducing GIDL(Gate Induced Drain Leakage) currents of transistors. A semiconductor flash memory device includes first strings(11,12) and a power supply unit. The first strings include plural unit cells which are disposed in series. The power supply unit supplies a program voltage to one unit cell selected from the first strings and a program preventing voltage to the rest unit cells. When the program voltage gradually increases, the program preventing voltage gradually decreases.