FLASH MEMORY DEVICE HAVING DUMMY TRANSISTOR

PURPOSE: A flash memory device is provided to reduce manufacturing costs and improve the integration rate of a memory device by using a dummy transistor in order to select a memory cell string which is structured to a common bit line. CONSTITUTION: A first memory cell string is connected to a bit line(BL) through a first and a second dummy transistor. A second memory cell string is connected to the bit line through a third and fourth dummy transistor. The first and the third dummy transistor are connected to a first dummy word line(DWL1). The second and the fourth dummy transistor are connected to a second dummy word line(DWL2). The threshold voltage of the first and the third dummy transistor is set to be different from each other. The threshold voltage of the second and the fourth dummy transistor is set to be different from each other.