Patent ID: 8912515

Claim:
A memory device, comprising: a first electrode comprising a pipe-shaped member having an axis, a first end, a second end and sidewalls having thickness in a dimension orthogonal to the axis of the pipe-shaped member, and having a ring-shaped surface at the second end, and a disc shaped member coupled to the first end of the pipe-shaped member, wherein the disc shaped member comprises a first material and has a thickness in a dimension coaxial with the pipe-shaped member that is not dependent on the thickness of the sidewalls of the pipe-shaped member, and the pipe-shaped member comprises a second material that different than the first material; a layer of programmable resistive material; the ring-shaped surface of the pipe-shaped member in direct electrical contact with a ring-shaped portion of a surface of the layer of programmable resistive material; and a second electrode in contact with the layer of programmable resistive material.