Patent ID: 8624214

Claim:
A semiconductor device, comprising: a semiconductor substrate; a plurality of transistors formed on the semiconductor substrate; a multi-layered wire structure including wires arranged in different layers via an insulating layer above the plurality of transistors, the multi-layered wire structure connecting a resistance variable element to the transistor, the resistance variable element being configured to change its resistance in response to voltages applied thereto; a first terminal and a second terminal which are formed above an uppermost wire of the multi-layered wire structure and are directly connected to the uppermost wire, or which are formed in a part of the uppermost wire; and a resistance variable layer which is arranged to cover and contact an upper surface of at least one of the first terminal and the second terminal, wherein: the resistance variable element is covered with only a moisture-resistant passivation layer without forming wires above the resistance variable element, and includes the first terminal, the resistance variable layer and the second terminal, a conductive layer is formed on the upper surface of the resistance variable layer and has a lower resistance than the resistance variable layer, the resistance variable layer includes two transition metal oxide layers which comprise a transition metal oxide and are different in oxygen concentration, a portion of the resistance variable layer, which is in contact with one of the first terminal, the second terminal and the conductive layer, is a transition metal oxide layer with higher oxygen concentration of the two transition metal oxide layers, and the resistance variable layer is arranged to cover and contact the upper surface of one of the first terminal and the second terminal, and the conductive layer is arranged to cover and contact the resistance variable layer and to cover and contact the upper surface of the other of the first terminal and the second terminal via a hole formed in the resistance variable layer.