1. A pressure switch assembly, comprising:
a semiconductor substrate;
a cavity defined within the semiconductor substrate having a cross-sectional area and a depth;
a bottom conductor disposed within the cavity;
a conductive membrane disposed above the cavity and adapted to deflect towards the bottom conductor upon an applied pressure;
an insulating layer disposed between the conductive membrane and the bottom conductor; and
a switching element adapted to activate upon electrical communication between the conductive membrane and the bottom conductor.
2. The pressure switch assembly of claim 1, wherein the conductive membrane is made from carbon nanotubes.
3. The pressure switch assembly of claim 1, wherein the conductive membrane is made from graphene.
4. The pressure switch assembly of claim 1, further comprising an insulating layer disposed on the surface of the semiconductor substrate.
5. The pressure switch assembly of claim 4, further comprising a top conductor pad disposed on the insulating layer.
6. The pressure switch assembly of claim 1, wherein the insulating layer disposed between the conductive membrane and the bottom conductor is elastic.
7. The pressure switch assembly of claim 1, wherein the insulating layer disposed between the conductive membrane and the bottom conductor is sufficiently thin to allow electron tunneling between the conductive membrane and the bottom conductor.
8. The pressure switch assembly of claim 7, wherein the insulating layer disposed between the conductive membrane and the bottom conductor is made of parylene.
9. The pressure switch assembly of claim 1, further comprising an isolation diaphragm encapsulating the conductive membrane.
10. The pressure switch assembly of claim 9, wherein the isolation diaphragm is made of metal.
11. The pressure switch assembly of claim 9, further comprising an incompressible liquid disposed between the isolation diaphragm and the conductive membrane.
12. The pressure switch assembly of claim 11, wherein the incompressible liquid comprises molecules having sizes that are too large to penetrate the membrane.
13. The pressure switch assembly of claim 1, wherein the cavity has a shape that is substantially rectangular.
14. The pressure switch assembly of claim 1, wherein the cavity has a shape that is substantially circular.
15. A method of indicating whether a pressure exerted by a medium is above a certain threshold pressure comprising:
applying the pressure to a conductive membrane suspended across a cavity, wherein the cavity has a cavity bottom and the pressure causes the conductive membrane to deflect toward the cavity bottom;
creating an electrical potential difference between the conductive membrane and the cavity bottom; and
activating a load when a current flows between the conductive membrane and the cavity bottom;
wherein a substantial increase in the current indicates the pressure is above the threshold pressure.
16. The method of claim 15, wherein the substantial increase in the current is an exponential increase.
17. The method of claim 15, further comprising reversing a polarity of the electrical potential difference to counteract van der Waals’ forces between the conductive membrane and the cavity bottom.
18. The method of claim 15, wherein applying the pressure to a conductive membrane further comprises physically isolating the conductive membrane from the medium.
19. The method of claim 18, wherein physically isolating the conductive membrane from the medium means transferring the pressure to the membrane via an isolation diaphragm and an incompressible liquid.
20. The method of claim 15, further comprising setting the threshold pressure by adjusting a distance between the conductive membrane and the cavity bottom.
21. A method of manufacturing a pressure switch comprising:
providing a substrate;
fabricating a cavity within the substrate wherein the cavity has a cavity bottom;
depositing a conductive material on the cavity bottom;
electrically isolating the conductive material on the cavity bottom;
disposing a conductive membrane across the cavity; and
defining contact pads on top of the conductive membrane;
wherein the depth and geometry of the cavity correspond to a desired threshold pressure of the pressure switch.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of making a product, comprising:
filling a hole defined in a body with Zn\u2014Al alloy in a molten state, said Zn\u2014Al alloy providing a conductor made of the Zn\u2014Al allow in a solid state at least partially exposed on a surface of the body;
forming a wiring on the surface of the body, the wiring connected to the conductor, and
applying heat at least to the conductor and the wiring such that the conductor diffuses into the wiring.
2. The method according to claim 1, wherein the Zn\u2014Al alloy contains aluminum at a content equal to or smaller than 1.0 weight %.
3. The method according to claim 1, wherein the Zn\u2014Al alloy contains aluminum at a content equal to or smaller than 20.0 weight %.
4. The method according to claim 1, wherein said conductor fills a through hole penetrating through the body.
5. The method according to claim 4, wherein an aspect ratio of the through hole is set equal to or larger than 3.
6. The method according to claim 1, wherein the body is made of glass, silicon or ceramic.
7. The method according to claim 1, wherein the body is a glass substrate, a silicon substrate or a ceramic substrate.
8. The method according to claim 1, wherein the wiring is made of aluminum or copper.
9. The method according to claim 1, wherein the wiring is a wiring pattern located on a surface of the body.
10. The method according to claim 1, wherein the wiring is made of aluminum.
11. A method of making a product, comprising:
filling a hold defined in a body with Zn\u2014Al alloy in a molten state, said Zn\u2014Al alloy providing a conductor made of the Zn\u2014Al alloy in a solid state at least partially exposed on a surface of the body; and
forming a wiring on the surface of the body in an oxygen-free atmosphere using a radio-frequency (RF) plasma, the wiring connected to the conductor.
12. The method according to claim 11, wherein the wiring is made of aluminum.