Patent ID: 8599602
Filing Date: 2013-12-03
Classification: G11C,H01L

Abstract:
1. A method of programming a variable resistance element which includes a transition metal oxide having resistance values that increase and decrease according to applied electric pulses, the transition metal oxide comprising a first transition metal oxide layer and a second transition metal oxide layer which are stacked, the second transition metal oxide layer having a degree of oxygen deficiency smaller than a degree of oxygen deficiency of the first transition metal oxide layer, said method comprising: performing at least one writing step by applying a writing voltage pulse having a first polarity to the transition metal oxide so as to change a resistance state of the transition metal oxide from high to low; and performing at least one erasing step by applying an erasing voltage pulse having a second polarity to the transition metal oxide so as to change the resistance state of the transition metal oxide from low to high, the second polarity being different from the first polarity, wherein |Vw |Ve tw the (N+1)-th writing step follows the M-th erasing step.