Memory device with a self-assembled polymer film and method of making the same
View Patent ↗A memory device with multi-bit memory cells and method of making the same uses self-assembly to provide polymer memory cells on the contacts to a transistor array. Employing self-assembly produces polymer memory cells at the precise locations of the contacts of the transistor array. The polymer memory cells change resistance values in response to electric current above a specified threshold value. The memory cells retain the resistivity values over time.
1. A method of assembling a memory device, comprising:
forming an array of transistors;
covering the transistors with a dielectric layer;
forming conductive contacts to the transistors through the dielectric layer, the forming of conductive contacts includes forming conductive plugs each having a bottom portion and a top portion, wherein the bottom portion contacts the transistors; forming a barrier layer on the top portion of the conductive plugs, and forming an adhesion layer on the barrier layer;
forming memory elements with multiple selectable resistance values on the conductive contacts by self-assembly, the forming of memory elements includes locating the memory device within an enclosed chamber with a liquid monomer; and
forming a common electrode on the memory elements connecting to each of the memory elements.
2. The method of claim 1 , wherein the forming of memory elements further includes depositing a first material that adheres only to the conductive contacts and not to the dielectric layer.
3. The method of claim 2 , wherein the first material is a polyconjugated polymer.
4. The method of claim 3 , wherein the polyconjugated polymer is one of polyparaphenylene, polyphenylvinylene, polyaniline, polythiophene or polypyrrole.
5. The method of claim 2 , wherein the first material is a polymeric phtalocyanine.
6. The method of claim 2 , wherein the first material is a polymeric porphyrin.
7. The method of claim 1 , wherein the forming of memory elements further includes locating the memory device within an enclosed chamber with a monomer gas.
8. The method of claim 7 , wherein the liquid monomer and the monomer gas are methylphenylacetylene, and a polyconjugated polymer of polymethylphenylacetylene is formed as the memory elements.
9. The method of claim 7 , wherein the liquid monomer and the monomer gas are tetracyanobenzene, and cupperphtalocyanine is formed as the memory elements.