Patent ID: 9601192
Date: 2017-03-21
CPC Classifications: G11C,H01L

Claim:
1. A resistance-change memory comprising: first and second electrodes; a variable resistance layer disposed between the first electrode and the second electrode; and a control circuit which applies a voltage between the first electrode and the second electrode, wherein the variable resistance layer can enter into one of an on-state, an off-state, and an intermediate state, a resistance of the off-state being greater than a resistance of the on-state, a resistance of the intermediate state being greater than the resistance of the on-state, and the variable resistance layer makes transitions to the on-state when the control circuit applies a first voltage pulse between the first electrode and the second electrode, the variable resistance layer in the on-state transitions to the intermediate state when the control circuit applies a second voltage pulse different in polarity from the first voltage pulse between the first electrode and the second electrode, the variable resistance layer in the intermediate state transitions to the off-state when the control circuit applies a third voltage pulse between the first electrode and the second electrode, at least one of pulse amplitude or pulse width of the third voltage pulse being greater than at least one of pulse amplitude or pulse width of the second voltage pulse respectively, and the variable resistance layer in the intermediate state transitions to the on-state when the control circuit applies a fourth voltage pulse between the first electrode and the second electrode, a product of pulse amplitude and pulse width of the fourth voltage pulse being smaller than a product of pulse amplitude and pulse width of the first voltage pulse, wherein, during a read operation, the variable resistance layer in the intermediate state transitions to the on-state and a read current flowing through the variable resistance layer in the on-state is read when the control circuit applies the fourth voltage pulse between the first electrode and the second electrode, and then the variable resistance layer returns to the intermediate state from the on-state when the control circuit applies the second voltage pulse between the first electrode and the second electrode.