Ferroelectric memory device
The invention relates to a ferroelectric memory device comprising at least one layer comprising a ferroelectric polymer, and at least two electrodes either side thereof, the ferroelectric polymer being of general formula P(VDF-X-Y), wherein VDF is vinylidene fluoride motifs, X is trifluoroethylene or tetrafluoroethylene motifs, and Y is motifs from a third monomer, the molar proportion of Y motifs in the polymer being less than or equal to 6.5%.
1. A non-volatile ferroelectric memory device comprising, in said non-volatile ferroelectric memory device, at least one layer which comprises a ferroelectric polymer and at least two electrodes on either side of this layer, the ferroelectric polymer being of general formula P(VDF-X-Y), in which VDF represents vinylidene fluoride units, X represents trifluoroethylene or tetrafluoroethylene units and Y represents tetrafluoroethylene, vinyl fluoride, perfluoro(alkyl vinyl) ether, bromotrifluoroethylene, chlorotrifluoroethylene, tetrafluoropropene, chlorotrifluoropropene, trifluoropropene or pentafluoropropene units, monomer, the molar proportion of Y units in the polymer has a value from 0.1 to 6.5%, and the ferroelectric polymer having a remanent polarization greater than 15 mC/m 2 .
2. The device as claimed in claim 1 , in which Y represents tetrafluoroethylene, vinyl fluoride, perfluoro(alkyl vinyl) ether, bromotrifluoroethylene, tetrafluoropropene, chlorotrifluoropropene, trifluoropropene or pentafluoropropene units.
3. The device as claimed in claim 1 , in which X represents trifluoroethylene units.
4. The device as claimed in claim 1 , in which the molar ratio of the VDF units to the X units in the polymer has a value from 55:45 to 80:20.
5. The device as claimed in claim 4 , wherein the molar ratio of VDF units to X units is 60:40 to 75:25.
6. The device as claimed in claim 1 , in which the layer of ferroelectric polymer has a thickness of less than 1 μm.
7. The device as claimed in claim 6 , wherein the layer of ferroelectric polymer has a thickness from 10 nm to 900 nm.
8. The device as claimed in claim 6 , wherein the layer of ferroelectric polymer has a thickness from 100 nm to 800 nm.
9. The device as claimed in claim 1 , comprising a semiconducting material, as a mixture with the ferroelectric polymer or in the form of a separate layer.
10. The device as claimed in claim 9 , wherein the semiconducting material is a semiconducting polymer.
11. The device as claimed in claim 1 , which comprises or which is a ferroelectric capacitor.
12. The device as claimed in claim 1 , which comprises or which is a ferroelectric field-effect transistor.
13. The device as claimed in claim 1 , which comprises or which is a ferroelectric diode.
14. The device as claimed in claim 1 , which is an integrated memory device comprising two arrays of electrodes on either side of the layer of ferroelectric polymer or on either side of a plurality of layers of the ferroelectric polymer.
15. The device as claimed in claim 1 , in which the ferroelectric polymer is deposited on a substrate by spin coating, spraying or printing.
16. The device as claimed in claim 1 , wherein the molar proportion of Y units is from 0.5 to 6%.
17. The device as claimed in claim 1 , wherein the molar proportion of Y units is from 2 to 5%.