Phase-change memory devices with a self-heater structure

A phase-change memory device comprising:

• a phase-change memory layer having a first surface facing a semiconductor substrate and a second surface which is opposite the first surface;
• a plurality of conductive layers between the semiconductor substrate and the phase-change memory layer;
• a plurality of contact plugs connected to the first surface of the phase-change memory layer such that the phase-change memory layer is electrically connected to ones of the plurality of conductive layers;
• and
• an insulating layer, which covers the second surface of the phase-change memory layer.

A phase-change memory device comprising:

• a lower electrode on a semiconductor substrate;
• an upper electrode on the lower electrode;
• a phase-change memory layer between the lower electrode and the upper electrode, the phase-change memory layer having a first surface adjacent the lower electrode;
• a first contact plug connected to the first surface of the phase-change memory layer and configured to supply an electric signal from the lower electrode to the phase-change memory layer;
• and
• a second contact plug connected to the upper electrode and the first contact plug.

A phase change memory device comprising:

• a phase-change memory layer on a semiconductor substrate, the phase-change memory layer having a major axis that is substantially parallel to a major axis of the semiconductor substrate and having a first surface and a second surface opposite the first surface that are substantially parallel to the major axis of the phase-change memory layer;
• a first electrode on the semiconductor substrate that is electrically connected to the first surface of the phase-change memory layer in a first contact region of the phase-change memory layer;
• and
• a second electrode on the semiconductor substrate that is electrically connected to the phase-change memory layer in a second contact region of the phase-change memory layer, the second contact region being space apart from the first contact region.