Phase change memory device and fabricating method
A phase change memory device is provided. The phase change memory device includes a substrate with a first electrode layer formed thereon. A first phase change memory structure is on the first electrode layer and electrically connected to the first electrode layer. A second phase change memory structure is on the first phase change memory structure and electrically connected to the first phase change memory structure, wherein the first or second phase change memory structure includes a cup-shaped heating electrode. A first insulating layer covers a portion of the cup-shaped heating electrode along a first direction. A first electrode structure covers a portion of the first insulating layer and the cup-shaped heating electrode along a second direction. The first electrode structure includes a pair of phase change material sidewalls on a pair of sidewalls of the first electrode structure and covering a portion of the cup-shaped heating electrode.
1. A method of fabricating a phase change memory device, comprising:
providing a substrate with a first electrode layer formed thereon;
forming a first phase change memory structure on the first electrode layer and electrically connected to the first electrode layer;
forming a second phase change memory structure on the first phase change memory structure and electrically connected to the first phase change memory structure, wherein the first phase change memory structure or the second phase change memory structure comprises:
forming a cup-shaped heating electrode in a first dielectric layer;
forming a first insulating layer on the first dielectric layer along a first direction parallel to a side of the cup-shaped heating electrode covering a portion of the cup-shaped heating electrode;
forming a first electrode structure along a second direction parallel to another side of the cup-shaped heating electrode and covering a portion of the first insulating layer and the cup-shaped heating electrode, wherein the first electrode structure comprises a pair of phase change material spacers disposed on a pair of sidewalls of the first electrode structure covering a portion of the cup-shaped heating electrode, thereby forming an intersectional contact area between one of the phase change material spacers and the cup-shaped heating electrode; and
forming a second dielectric layer on the first insulating layer and the first dielectric layer and adjacent the first electrode structure.
2. The method of fabricating the phase change memory device as claimed in claim 1 , further comprising:
forming a p-type semiconductor layer and an n-type semiconductor layer on the first electrode layer by thin film deposition;
removing a portion of the p-type semiconductor layer and the n-type semiconductor to form a diode by photolithography and etching processes;
forming a first dielectric layer on the first electrode layer and the diode with covering the diode before forming the cup-shaped heating electrode.
3. The method of fabricating the phase change memory device as claimed in claim 2 , further comprising:
removing a portion of the first dielectric layer until the diode is exposed forming a cup-shaped opening by photolithography and etching processes;
forming a conductive layer in the cup-shaped opening, wherein the conductive layer is cup-shaped;
forming a third insulating layer on the conductive layer, the third insulating layer filling the cup-shaped opening; and
performing a planarized process to remove a portion of the conductive layer and the third insulation layer to form the cup-shaped heating electrode.
4. The method of fabricating the phase change memory device as claimed in claim 1 , wherein the first insulating layer covers at least one edge of the cup-shaped heating electrode.
5. The method of fabricating the phase change memory device as claimed in claim 1 , wherein the first insulating layer covers at least one edge of the cup-shaped heating electrode.
6. The method of fabricating the phase change memory device as claimed in claim 1 , further comprising:
forming a stacked structure comprising a fourth insulating layer and a conductive layer On the first dielectric layer;
covering a phase change material layer on the stacked structure; and
removing a portion of the phase change material layer by anisotropic etching to form a pair of phase change material spacers on a pair of sidewall of the stacked structure to form the first electrode structure.