Patent ID: 9087582
Filing Date: 2015-07-21
Classification: G11C

Abstract:
1. A method of driving a non-volatile memory element including: a variable resistance element including a first electrode, a second electrode, and a variable resistance layer which is disposed between the first electrode and the second electrode and reversibly changes its resistance state between a low-resistance state and a high-resistance state in which a resistance value is greater than a resistance value corresponding to the low-resistance state, in response to a voltage pulse applied between the first electrode and the second electrode; and a field effect transistor including a first input/output terminal connected to the first electrode, a second input/output terminal, and a gate terminal for controlling electric conduction between the first input/output terminal and the second input/output terminal, the method comprising: applying an erase voltage pulse with a first polarity between the second electrode and the second input/output terminal, to change the variable resistance layer from the low-resistance state to the high-resistance state; applying a write voltage pulse with a second polarity which is different from the first polarity, between the second electrode and the second input/output terminal, to change the variable resistance layer from the high-resistance state to the low-resistance state; wherein the second polarity is such that the second input/output terminal of the field effect transistor becomes a source terminal; applying a first gate voltage to the gate terminal of the field effect transistor, when a first write voltage pulse is applied between the second electrode and the second input/output terminal, to change the variable resistance layer in the high-resistance state to the low-resistance state; and applying a second gate voltage which is smaller in absolute value than the first gate voltage, to the gate terminal of the field effect transistor, when a second write voltage pulse which is greater in absolute value of voltage than the first write voltage pulse is applied between the second electrode and the second input/output terminal, to change the variable resistance layer in an excess-resistance state to the low-resistance state.