MEMORY CELL PROGRAMMED USING TEMPERATURE CONTROLLED SET PULSE

摘要

PROBLEM TO BE SOLVED: To provide a phase change memory which can store three or more states.

SOLUTION: A memory cell 202 includes a phase change material 204 arranged in an insulation material 206. The phase change material 204 is electrically coupled at one end to a first electrode 208 and at the other end to a second electrode 210. A pulse is supplied to the memory cell 202 through the first electrode 208 and the second electrode 210. A current path through the phase change material 204 is from either one of the first electrode 208 and second electrode 210 to the other one of the first electrode 208 and second electrode 210. The phase change material 204 is programmed into one of four states for storing two bits of data. A selection device is coupled to the first electrode 208 to control the pulse supply to the phase change material 204. The pulse resets the phase change material 204 and programs one of the other three states into the phase change material 204.

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