Patent ID: 8737115

Claim:
A method of a forming process for a variable resistive element provided with a variable resistor formed of a metal oxide, and a first electrode and a second electrode sandwiching the variable resistor, wherein a resistance state between the first and second electrodes in the variable resistive element is lowered by the forming process, so that the variable resistive element is changed from an initial high resistance state to a variable resistance state in which the resistance state is switched between two or more different resistance states by an applied voltage, the variable resistive element in the variable resistance state is allowed to hold the resistance state in a non-volatile manner, and the forming process comprises: a first step of applying a first pulse having a voltage amplitude set to be lower than a threshold voltage at which the resistance of the variable resistive element is lowered, to between the first and second electrodes of the variable resistive element; and a second step of applying a second pulse having a voltage amplitude having the same polarity as that of the first pulse and set to be not lower than the threshold voltage, to between the first and second electrodes of the variable resistive element after the first step.