Resistance variable memory device with nanoparticle electrode and method of fabrication
View Patent ↗A chalcogenide-based programmable conductor memory device and method of forming the device, wherein a nanoparticle is provided between an electrode and a chalcogenide glass region. The method of forming the nanoparticle utilizes a template over the electrode or random deposition of the nanoparticle.
1. A method of forming a memory device, comprising:
providing a first electrode;
providing a nanoparticle over said first electrode;
providing a chalcogenide glass over and surrounding the nanoparticle except where the nanoparticle is in contact with said first electrode; and
providing a second electrode over said chalcogenide glass.
2. The method of claim 1 , wherein said nanoparticle comprises an inert, conductive material.
3. The method of claim 1 , wherein said nanoparticle comprises a material selected from the group consisting of tungsten, titanium nitride, platinum, palladium, ruthenium and alloys of tungsten, titanium nitride, platinum, palladium, and ruthenium.
4. The method of claim 1 , wherein providing a nanoparticle comprises providing a template over said first electrode and providing said nanoparticle through the template.
5. The method of claim 4 , wherein said template comprises anodic aluminum oxide having at least one nanochannel exposing the first electrode.
6. The method of claim 5 , wherein said nanoparticle is formed through said at least one nanochannel.
7. The method of claim 5 , wherein the positioning of said at least one nanochannel is controlled by adjusting at least one of an anodizing voltage, an electrolyte composition, and a temperature during the forming of said anodic aluminum oxide layer.
8. The method of claim 4 , wherein said template comprises a self-assembled diblock copolymer layer having at least one nanopore exposing said first electrode.
9. The method of claim 8 , wherein said self-assembled diblock copolymer layer comprises polystyrene and polymethylmetacrylate.
10. The method of claim 8 , wherein said nanoparticle is formed within said at least one nanopore.
11. The method of claim 4 , wherein about one nanoparticle is formed over said first electrode.
12. The method of claim 1 , wherein said nanoparticle is deposited over said first electrode by chemical vapor deposition.
13. The method of claim 12 , wherein said chemical vapor deposition is controlled so as to deposit about one nanoparticle over said first electrode.
14. The method of claim 1 , wherein said chalcogenide glass comprises germanium selenide.
15. The method of claim 14 , wherein said germanium selenide has a stoichiometry of about Ge 2 Se 3 .
16. The method of claim 1 , further comprising providing metal chalcogenide between said chalcogenide glass and said second electrode.
17. The method of claim 16 , further comprising:
providing a second chalcogenide glass between said metal chalcogenide and said second electrode;
providing a metal between said second chalcogenide glass and said second electrode; and
providing a third chalcogenide glass between said metal and said second electrode.
18. A method of forming a chalcogenide-based programmable conductor memory device, comprising:
providing a first electrode;
providing a nanoparticle over said first electrode, said nanoparticle providing step comprising:
forming a self-assembled diblock copolymer layer over said first electrode,
forming about one nanopore to said first electrode through said self-assembled diblock copolymer layer,
depositing a nanoparticle material over said self-assembled diblock copolymer layer, within said about one nanopore, and over said first electrode where exposed in said nanopore, and
selectively removing said self-assembled diblock copolymer layer and the nanoparticle material such that a nanoparticle remains on said first electrode; and
providing a chalcogenide glass over said first electrode and said nanoparticle, said chalcogenide glass comprising germanium selenide.
19. The method of claim 18 , wherein said self-assembled diblock copolymer comprises polystyrene and polymethylmethacrylate.
20. The method of claim 18 , wherein said forming the self-assembled diblock copolymer comprises spinning said self-assembled diblock copolymer onto the first electrode in a toluene solution.
21. The method of claim 18 , wherein said forming said nanopore comprises annealing said self-assembled diblock copolymer layer at a temperature above its glass transition temperature and applying an electric field perpendicular to said first electrode layer such that a polymethylmethacrylate cylinder is formed; and
removing said polymethylmethacrylate cylinder to leave the about one nanopore.
22. The method of claim 18 , wherein the deposition of the nanoparticle material comprises physical vapor deposition.
23. The method of claim 18 , wherein said nanoparticle has a diameter of about 3 nm to about 20 nm.
24. The method of claim 18 , wherein said nanoparticle has a diameter of about 10 nm.
25. The method of claim 18 , wherein said nanoparticle comprises an inert, conductive material.
26. The method of claim 18 , wherein said nanoparticle comprises a material selected from the group consisting of tungsten, titanium nitride, platinum, palladium, ruthenium and alloys of tungsten, titanium nitride, platinum, palladium, and ruthenium.