Patent ID: 7965539

Claim:
A nonvolatile memory element comprising: a first electrode; a second electrode; and a resistance variable layer which intervenes between the first electrode and the second electrode, a resistance value of the resistance variable layer changing reversibly in response to electric pulses applied between the first electrode and the second electrode; wherein the resistance variable layer is configured to include at least an oxide of a metal element of IV group, V group or VI group; wherein when among voltages V 1 to V 6 of electric pulses applied between the first electrode and the second electrode, the voltage V 1 , the voltage V 4 and the voltage V 6 are positive voltages and have a relationship V 1 >V 4 >V 6 , and the voltage V 2 , the voltage V 3 , and the voltage V 5 are negative voltages and have a relationship V 5 >V 3 >V 2 , (A) the resistance value of the resistance variable layer becomes a high-resistance value R H when the electric pulse of the voltage V 1 is applied between the first electrode and the second electrode, thereafter the resistance value maintains the high-resistance value R H when an electric pulse of a positive voltage is applied between the first electrode and the second electrode, while the resistance value decreases when an electric pulse of a negative voltage which is smaller than the voltage V 5 and larger than the voltage V 3 is applied between the first electrode and the second electrode, the resistance value becomes a low-resistance value R L when the electric pulse of the voltage V 3 is applied between the first electrode and the second electrode, then increases when an electric pulse of a negative voltage which is smaller than the voltage V 3 and larger than the voltage V 2 is applied between the first electrode and the second electrode or becomes the high-resistance value R H when the electric pulse of the voltage V 2 is applied between the first electrode and the second electrode, (B) after the electric pulse of the voltage V 2 is applied between the first electrode and the second electrode, the resistance value maintains the high-resistance value R H when an electric pulse of a negative voltage is applied between the first electrode and the second electrode, while the resistance value decreases when an electric pulse of a positive voltage which is larger than the voltage V 6 and smaller than the voltage V 4 is applied between the first electrode and the second electrode, the resistance value becomes the low-resistance value R L when the electric pulse of the voltage V 4 is applied between the first electrode and the second electrode, and then increases when an electric pulse of a positive voltage which is larger than the voltage V 4 and smaller than the voltage V 1 is applied between the first electrode and the second electrode, or becomes the high-resistance value R H when the electric pulse of the voltage V 1 is applied between the first electrode and the second electrode.