Fixed parallel plate MEMS capacitor microsensor array
A fixed parallel plate micro-mechanical systems (MEMS) based sensor is fabricated to allow a dissolved dielectric to flow through a porous top plate, coming to rest on a bottom plate. A post-deposition bake ensures further purity and uniformity of the dielectric layer. In one embodiment, the dielectric is a polymer. In one embodiment, a support layer is deposited onto the top plate for strengthening the sensor. In another embodiment, the bottom plate is dual-layered for a narrowed gap. Integrated circuit arrays of such sensors can be made, having multiple devices separated from each other by a physical barrier, such as a polycrystalline containment rim or trough, for preventing polymer material from one sensor from interfering with that of another.
1. A microsensor array, comprising:
a. a substrate;
b. a plurality of microsensors disposed on the substrate, at least one of which is a fixed, parallel plate capacitive microsensor comprising:
i. a bottom plate electrode disposed on the substrate;
ii. a porous top plate electrode disposed in fixed, spaced relation to the bottom plate electrode; and
iii. a dielectric disposed between said bottom plate electrode and said top plate electrode; and, optionally,
c. a containment barrier disposed between at least two of the microsensors disposed on the substrate.
2. A microsensor array according to claim 1 , wherein each of the microsensors is a fixed, parallel plate capacitive microsensor.
3. A microsensor array according to claim 2 , wherein each fixed, parallel plate capacitive microsensor comprises:
a. a bottom plate electrode disposed on the substrate;
b. a porous top plate electrode disposed in fixed, spaced relation to the bottom plate electrode; and
c. a dielectric disposed between said bottom plate electrode and said top plate electrode.
4. A microsensor array according to claim 1 further comprising a containment barrier disposed between each of the microsensors disposed on the substrate.
5. A microsensor array according to claim 4 , wherein each of the containment barriers is adapted to prevent leakage of the dielectric of one microsensor to another microsensor during manufacture of the microsensors.
6. A microsensor array according to claim 4 , wherein each containment barrier is independently selected from the group consisting of a polymer and a metal.
7. A microsensor array according to claim 4 , wherein each containment barrier is comprised of a polymer.
8. A microsensor array according to claim 4 , wherein each containment barrier is comprised of a metal.
9. A microsensor array according to claim 4 , wherein each containment barrier is independently shaped as a rim or a trough.
10. A microsensor array according to claim 4 , wherein diaelectric material is applied by a deposition process.
11. A microsensor array according to claim 1 , wherein at least two of the microsensors are fixed, parallel plate capacitive microsensors each comprise a dielectric disposed between a bottom plate electrode and a top plate electrode.
12. A microsensor array according to claim 11 , wherein each of the fixed, parallel plate capacitive microsensors comprises a different dielectric material.
13. A microsensor array according to claim 12 , wherein the different dielectric materials each have a different dielectric constant.
14. A microsensor array according to claim 11 , wherein each dielectric material is independently selected from the group consisting of a polymer, a ceramic, and a solgel.
15. A microsensor array according to claim 1 , wherein the porous top plate electrode of any fixed, parallel plate capacitive microsensor is fabricated using standard photolithography.
16. A microsensor array according to claim 1 further comprising one or more support layers deposited onto the porous top plate electrode(s).
17. A microsensor array according to claim 1 , wherein any bottom plate electrode is a drive electrode.
18. A microsensor array according to claim 1 , wherein any bottom plate electrode is a dual-layer electrode.
19. A microsensor array according to claim 1 , wherein any porous top plate electrode and bottom plate electrode of a fixed, parallel plate capacitive microsensor is made from a polycrystalline semiconductor material or a metal.