Electronic and optical devices and methods of forming these devices

1. A variable electronic device for coupling or modifying a signal, said device comprising:

a variable dielectric material portion; and

at least one biasing electrode for applying an electric field to said variable dielectric material portion to thereby change the dielectric constant of the variable dielectric material portion; wherein

said at least one biasing electrode is thin enough to present a larger impedance to the signal than said variable dielectric material portion, and is conductive enough to apply the electric field, and said at least one biasing electrode has a DC resistivity of between 10 Ω/square and 10 MΩ/square.

2. The variable device of claim 1 , wherein said at least one biasing electrode is between 5 nm and 0.5 nm thick.

3. A method of forming the electronic device of claim 1 , said method comprising the steps of:

providing said substrate;

depositing a variable dielectric material layer on top of said substrate to form said variable dielectric material portion;

depositing a photoresist layer on top of said dielectric material layer, said photoresist layer covering a first portion of said dielectric material layer and not covering a second portion of said dielectric material layer;

etching away the second portion of said dielectric material layer to form an exposed subtrate portion;

depositing a conductive material layer on top of said photoresist layer and on said exposed substrate portion said conductive material layer having a first portion on top of said photoresist layer, and a second portion directly contacting on said exposed substrate portion; and

removing said first portion of said conductive material layer; wherein

said second portion of said conductive material layer remains as said said at least one biasing electrode which is in direct contact with said dielectric material layer.

4. The variable device of claim 1 , wherein said at least one biasing electrode has a DC resistivity of between 100 Ω/square and 1 MΩ/square.

5. The variable device of claim 1 , wherein said at least one biasing electrode is comprised of a material that is a mixed conductor.

6. The variable device of claim 1 , wherein said at least one biasing electrode is comprised of a material that is predominately an ionic conductor.

7. The variable device of claim 1 , wherein said at least one biasing electrode is comprised of a material that is a semiconductor.

8. The variable device of claim 1 , wherein said at least one biasing electrode is comprised of a material that is a conductive oxide.

9. The variable device of claim 1 , wherein said at least one biasing electrode is comprised of a material that has reduced grain boundaries or is epitaxial.

10. A variable electronic device for coupling or modifying a signal, said device comprising:

a variable dielectric material portion; and

at least one biasing electrode for applying an electric field to said variable dielectric material portion to thereby change the dielectric constant of the variable dielectric material portion; wherein

said at least one biasing electrode has a resistance to the signal that is at least 25% greater than its DC resistance.

11. The variable device of claim 10 , wherein said at least one biasing electrode has a resistance to the signal that is at least 100% greater than its DC resistance.

12. A variable electronic device for coupling or modifying a signal, said device comprising:

a variable dielectric material portion;

a main electrode portion for routing an electric signal through the variable dielectric portion; and

at least one biasing electrode for applying an electric field to said variable dielectric material portion to thereby change the dielectric constant thereof and wherein said at least one biasing electrode is between 200 nm and 0.3nm in thickness.

13. The variable electronic device of claim 12 , wherein:

said at least one biasing electrode includes a first biasing electrode and a second biasing electrode; and

said first and second biasing electrodes are on opposite surfaces of said variable dielectric material.

14. The variable electronic device of claim 12 , wherein:

said at least one biasing electrode includes a first biasing electrode and a second biasing electrode; and

said first and second biasing electrodes are on the same surface of said variable dielectric material.

15. The variable electronic device of claim 12 , wherein: said main electrode portion includes a first main electrode and a second main electrode;

said at least one biasing electrode includes a first biasing electrode and a second biasing electrode;

said first main electrode is electrically connected to said first biasing electrode; and

said second main electrode is electrically connected to said second biasing electrode.

16. The variable electronic device of claim 12 , wherein said main electrode portion and said at least one biasing electrode are spaced less than 10 microns apart.

17. The variable electronic device of claim 12 , wherein said at least one biasing electrode presents a higher impedance to the signal than the variable dielectric material.

18. The variable electronic device of claim 12 , wherein said at least one biasing electrode is adjacent to said main electrode portion.

19. A tunable or variable device comprising:

a substrate having a surface;

a variable dielectric material on a portion of the substrate surface;

RF electrodes; and

electrodes that function as biasing electrodes, the biasing electrodes being in direct contact with both the variable dielectric material and the surface of the substrate and wherein

said RF electrodes have a thickness;

adjacent biasing electrodes are separated by a gap having a width; and

the thickness of said RF electrodes is at least 50% of the width of the gap.

20. The tunable or variable device of claim 19 wherein the thickness of said RF electrodes is at least 100% of the width of the gap.

21. The tunable or variable device of claim 19 wherein the thickness of said RF electrodes is at least 200% of the width of the gap.

22. The tunable or variable device of claim 19 wherein:

the variable dielectric material has a first surface in contact with the portion of the substrate surface, and a second surface opposite the first surface; and the biasing electrodes are predominately in contact with the substrate surface.

23. The tunable or variable device of claim 22 wherein the biasing electrodes overlap the second surface of the variable dielectric material by 25 microns.