PHASE CHANGEABLE MEMORY DEVICE HAVING MULTI-LEVE AND METHOD OF DRIVING THE SAME

摘要

PURPOSE: A phase change memory device and a driving method thereof are provided to implement multi levels by comprising a plurality of switching elements which are serially connected to a variable resistor to shift the distribution of resistance. CONSTITUTION: A variable resistor(Rv) is changed into set and reset status according to an applied current. A shifting unit(Su) is connected to the variable resistor and shifts the distribution of the set and reset resistance of the variable resistor with a preset level. The shifting unit is comprised of a plurality of switching elements which are serially connected. The variable resistor is connected between one bit line and the shifting unit.