Patent ID: 8309946

Claim:
A resistance variable element comprising: a first electrode; a second electrode; and a resistance variable layer which is interposed between the first electrode and the second electrode to contact the first electrode and the second electrode, the resistance variable layer being configured to reversibly change resistivity in response to electric signals with different polarities which are applied between the first electrode and the second electrode, wherein: the resistance variable layer includes a stacked layer structure including a first oxygen-deficient transition metal oxide layer and a second oxygen-deficient transition metal oxide layer with higher oxygen content than the first oxygen-deficient transition metal oxide layer, the second oxygen-deficient transition metal oxide layer is in contact with the second electrode, a material of the second electrode has crystal grains having grain boundaries, the material of the second electrode has protrusions at an interface between the second oxygen-deficient transition metal oxide layer and the second electrode, the protrusions protruding from the grain boundaries, and the second oxygen-deficient transition metal oxide layer has locally thinned portions at concave portions corresponding to the protrusions.