NAND FLASH MEMORY DEVICE AND METHOD OF FABRICATING THE SAME

A NAND-type flash memory device and a fabricating method thereof are provided to reduce the area of a semiconductor substrate required for select transistors by forming the select transistors on memory transistors. Active regions are defined by an isolation layer pattern disposed in a predetermined region of a semiconductor substrate. Memory transistors constitute a cell string, including memory gate patterns crossing the upper part of the active regions. Select transistors are disposed on the memory transistors. Lower plugs electrically connect the active regions at both sides of the cell string and the select transistors. The log plug is made of single crystalline silicon having a conductivity type different from that of the semiconductor substrate. A dummy gate pattern is disposed between two adjacent cell strings, running in parallel with the memory gate pattern.