Thin film non volatile memory device scalable to small sizes
A thin film non volatile memory scalable to small sizes and its fabrication process are disclosed. The thin film memory includes a thin film transistor control circuitry fabricated on a flexible substrate, together with an optoelectronic cross bar memory employing a photoconducting material. The thin film non volatile memory can be used in RFID communication tag with the control circuitry further employing wireless communication circuitry such as an antenna, a receiver, and a transmitter.
1. A flexible non-volatile memory device comprising
a flexible substrate;
a thin film transistor control circuitry formed on the flexible substrate; and
an optoelectronic cross bar memory in communication with the control circuitry, the optoelectronic cross bar memory comprising
a photoconductive thin film;
a plurality of bottom electrodes and a plurality of top electrodes arranged in a cross bar configuration, sandwiching the photoconductive thin film to provide an electric field to selected portion of the photoconductive thin film; and
an electromagnetic radiation source to irradiate a portion of the photoconductive thin film;
wherein the photoconductive thin film stores trapped charges generated by the electromagnetic radiation.
2. A device as in claim 1 wherein the flexible substrate is a plastic or paper substrate.
3. A device as in claim 1 wherein the photoconductive film thickness is between 1 to 2 μm.
4. A device as in claim 1 wherein the photoconductive film is (metal)(beta-decoxyethyl)porphyrins wherein the metal is selected from a group consisting of Cu, Co, Ni, Pd.
5. A device as in claim 1 wherein the photoconductive film is zinc-octakis(beta-decoxyethyl)porphyrins.
6. A device as in claim 1 wherein the photoconductive film is phthalocyanine, an aromatic compound, or an organo-metallic compound.
7. A device as in claim 1 wherein the electromagnetic radiation source is a visible, infrared or ultraviolet light source.
8. A device as in claim 1 wherein the optoelectronic cross bar memory is positioned on top of thin film transistor control circuitry.
9. A device as in claim 1 wherein the optoelectronic cross bar memory is positioned on the flexible substrate, beside the thin film transistor control circuitry.
10. A device as in claim 1 wherein the top electrode material is transparent to the electromagnetic radiation.
11. A device as in claim 1 wherein the top electrode material is indium tin oxide, another inorganic transparent conducting oxide, a conducting polymer, or poly(ethylenedioxythiophene).
12. A device as in claim 1 wherein the electromagnetic radiation source is positioned on top of the top electrodes.
13. A device as in claim 1 wherein the electromagnetic radiation source is positioned on the edge of the top electrodes.
14. A RFID device comprising
a semiconductor substrate;
a transistor control circuitry formed on the semiconductor substrate comprising a wireless communication circuit; and
an optoelectronic cross bar memory in communication with the control circuitry, the optoelectronic cross bar memory comprising
a photoconductive thin film;
a plurality of bottom electrodes and a plurality of top electrodes arranged in a cross bar configuration, sandwiching the photoconductive thin film to provide an electric field to selected portion of the photoconductive thin film; and
an electromagnetic radiation source to irradiate a portion of the photoconductive thin film;
wherein the photoconductive thin film stores trapped charges generated by the electromagnetic radiation.
15. A device as in claim 14 wherein the wireless communication circuit employs IR communication protocol.
16. A device as in claim 14 wherein the wireless communication circuit employs microwave communication protocol.
17. A device as in claim 14 wherein the wireless communication circuit employs radio frequency communication protocol.
18. A device as in claim 14 further comprising a battery to supply power to the whole circuitry.
19. A device as in claim 18 wherein the battery is a thin film battery.
20. A device as in claim 14 wherein the wireless communication circuit comprises an antenna.
21. A device as in claim 14 wherein the flexible substrate is a plastic or paper substrate.
22. A device as in claim 14 wherein the photoconductive film thickness is between 1 to 2 μm.
23. A device as in claim 14 wherein the photoconductive film is (metal)(beta-decoxyethyl)porphyrins wherein the metal is selected from a group consisting of Cu, Co, Ni, Pd.
24. A device as in claim 14 wherein the photoconductive film is zinc-octakis(beta-decoxyethyl)porphyrins.
25. A device as in claim 14 wherein the photoconductive film is phthalocyanine, an aromatic compound, or an organo-metallic compound.
26. A device as in claim 14 wherein the electromagnetic radiation source is a visible, infrared or ultraviolet light source.