US Patent 7668002 Resistance memory element and nonvolatile semiconductor memory

A resistance memory element, which memorizes a high resistance state and a low resistance state and switches between the high resistance state and the low resistance state by an application of a voltage, includes a pair of electrodes and a resistance memory layer sandwiched between the pair of electrodes and including a first layer of a first resistance memory material and a second layer of a second resistance memory material. The current value of the resistance memory element in the writing operation can be drastically decreased, and a nonvolatile semiconductor memory device of high integration and low electric power consumption can be formed.