Phase-change nonvolatile memory and manufacturing method therefor

A phase-change nonvolatile memory comprising:

• a semiconductor substrate;
• a lower electrode formed on the semiconductor substrate;
• a first interlayer insulating film which is formed to cover the lower electrode and the semiconductor substrate, wherein a first hole is formed in the first insulating film so as to expose the lower electrode;
• an impurity diffusion layer embedded in the first hole, wherein the impurity diffusion layer is constituted of a first semiconductor layer and a second semiconductor layer which have different conductivity types;
• a second interlayer insulating film which is formed to cover the first interlayer insulating film and the impurity diffusion layer, wherein a second hole is formed in the second interlayer insulating film so as to expose the impurity diffusion layer;
• a phase-change recording layer which is formed to cover the second interlayer insulating film and to embed the second hole;
• and
• an upper electrode formed on the phase-change recording layer,
• wherein the first semiconductor layer is constituted of a base portion which is formed inside the first hole so as to cover the lower electrode and a projecting portion which projects from the base portion so that a heating spot thereof comes in contact with the phase-change recording layer in the second hole, while the second semiconductor layer is formed to at least partially surround the projecting portion,
• wherein a depletion layer is formed in proximity to a junction surface formed between the first semiconductor layer and the second semiconductor layer so as to reduce a diameter of the heating spot, and
• wherein the heating spot heats the phase-change recording layer in response to a current flowing between the impurity diffusion layer and the phase-change recording layer.