Patent ID: 9064573
Filing Date: 2015-06-23
Classification: G11C

Abstract:
1. A writing method of a variable resistance non-volatile memory element, in which a voltage pulse is applied to the variable resistance non-volatile memory element to reversibly change a resistance state of the variable resistance non-volatile memory element, the variable resistance non-volatile memory element including a first electrode, a second electrode, and a variable resistance layer sandwiched between the first electrode and the second electrode; the variable resistance layer including a first metal oxide layer which is in contact with the first electrode, and a second metal oxide layer which is in contact with the second electrode and is lower in degree of oxygen deficiency than the first metal oxide layer; the variable resistance non-volatile memory element having a characteristic in which the variable resistance non-volatile memory element changes the resistance state from a first resistance state used to store first information to a second resistance state used to store second information by application of a pulse of a first voltage, and changes the resistance state from the second resistance state to the first resistance state by application of a pulse of a second voltage which is different in polarity from the first voltage; the writing method comprising: determining, in a first determination step, whether or not the resistance state of the variable resistance non-volatile memory element does not switch to the first resistance state and remains in the second resistance state, when the pulse of the second voltage is applied to the variable resistance non-volatile memory element; and when it is determined that the resistance state of the variable resistance non-volatile memory element does not switch to the first resistance state and remains in the second resistance state in the first determination step, applying, in a recovery step, at least once to the variable-resistance non-volatile memory element a recovery voltage pulse set composed of two pulses which are a first recovery voltage pulse which has the same polarity as that of the first voltage and a second recovery voltage pulse which has the same polarity as that of the second voltage, has a greater amplitude than the second voltage, and is applied subsequently to the first recovery voltage pulse.