High-temperature pressure sensor
View Patent ↗A high-temperature pressure sensor that includes a dielectric layer. The pressure sensor also includes a substrate capable of withstanding temperatures greater than 450° C. without entering a phase change, at least one semiconducting material deposited on the sapphire substrate, and a silicon dioxide layer deposited over the semiconducting material. One aspect of the pressure sensor includes a second semiconducting material.
1. A high-temperature pressure sensor, comprising:
a substrate capable of withstanding temperatures greater than 500° C. without entering a phase change;
a first semiconducting material deposited on said sapphire substrate; and
a dielectric material deposited over said first semiconducting material.
2. The high-temperature pressure sensor of claim 1 , comprising a silicon nitride layer deposited over said dielectric material.
3. The high-temperature pressure sensor of claim 1 , comprising a metallic or ohmic first contact on said dielectric material.
4. The high-temperature pressure sensor of claim 3 , comprising a metallic or ohmic second contact positioned adjacent to at least said dielectric material.
5. The high-temperature pressure sensor of claim 1 , wherein said dielectric material comprises at least one from the group consisting of silicon dioxide, silicon nitride, and any combinations thereof.
6. The high-temperature pressure sensor of claim 1 , wherein said substrate comprises sapphire, silicon, group III nitrides, silicon carbide, aluminum nitride, quartz, or sapphire ceramic.
7. The high-temperature pressure sensor of claim 1 , wherein said first semiconducting material exhibits piezoelectric characteristics.
8. The high-temperature pressure sensor of claim 1 , wherein said first semiconducting material comprises at least one from the group consisting of group III nitrides and silicon carbide.
9. The high-temperature pressure sensor of claim 8 , wherein said first semiconducting material comprises gallium nitride.
10. The high-temperature pressure sensor of claim 1 , comprising a second semiconducting material deposited on said first semiconducting material.
11. The high-temperature pressure sensor of claim 10 , wherein said second semiconducting material exhibits piezoelectric characteristics.
12. The high-temperature pressure sensor of claim 10 , wherein said second semiconducting material comprises an alloy of group III nitrides.
13. The high-temperature pressure sensor of claim 12 , wherein said second semiconducting material comprises aluminum gallium nitride.
14. The high-temperature pressure sensor of claim 4 , comprising a circuit between said first and second contacts for measuring a response of the pressure sensor to a force.
15. The high-temperature pressure sensor of claim 14 , wherein the response comprises a piezoelectric response.
16. The high-temperature pressure sensor of claim 15 , wherein the piezoelectric response comprises a change in capacitance.
17. The high-temperature pressure sensor of claim 16 , comprising a second capacitor that serves as a reference capacitor.
18. The high-temperature pressure sensor of claim 3 , comprising a metallic or ohmic second contact positioned on said substrate.
19. The high-temperature pressure sensor of claim 1 , wherein said substrate is selectively etched to define a diaphragm.
20. The high-temperature pressure sensor of claim 1 , wherein said substrate and said first semiconducting material are etched to define a cantilever.
21. The high-temperature pressure sensor of claim 20 , wherein a diaphragm is attached to the cantilever to transmit pressure.
22. A high-temperature pressure sensor, comprising:
a substrate capable of withstanding temperatures greater than 500° C. without entering a phase change;
a first semiconducting material deposited on said sapphire substrate, said first semiconducting material comprising gallium nitride;
a second semiconducting material deposited on said first semiconducting material; and
an insulator material deposited over said second semiconducting material.
23. The high-temperature pressure sensor of claim 22 , comprising a silicon nitride layer deposited over said insulator material.
24. The high-temperature pressure sensor of claim 22 , wherein said second semiconducting material exhibits piezoelectric characteristics.
25. The high-temperature pressure sensor of claim 22 , wherein said first semiconducting material comprises an alloy of a group III nitride.
26. The high-temperature pressure sensor of claim 25 , wherein said first semiconducting material comprises aluminum gallium nitride.
27. The high-temperature pressure sensor of claim 23 , comprising a metallic or ohmic first contact on said silicon nitride layer.
28. The high-temperature pressure sensor of claim 27 , comprising a metallic or ohmic second contact positioned adjacent to at least said silicon nitride layer.
29. The high-temperature pressure sensor of claim 28 , comprising a circuit between said first and second contacts for measuring a response of the pressure sensor to a force.
30. The high-temperature pressure sensor of claim 29 , wherein the response comprises a piezoelectric response.
31. The high-temperature pressure sensor of claim 30 , wherein the piezoelectric response comprises a change in capacitance.
32. The high-temperature pressure sensor of claim 31 , comprising a temperature compensation capacitor that serves as a reference capacitor.
33. The high-temperature pressure sensor of claim 27 , comprising a metallic or ohmic second contact positioned on said substrate.
34. The high-temperature pressure sensor of claim 22 , wherein said substrate is selectively etched to define a diaphragm.
35. The high-temperature pressure sensor of claim 22 , wherein said substrate and said first semiconducting material are etched to define a cantilever.
36. The high-temperature pressure sensor of claim 35 , wherein a diaphragm is attached to the cantilever to transmit pressure.
37. A method for fabricating a high-temperature pressure sensor, comprising:
depositing a first semiconducting material on a substrate capable of withstanding temperatures greater than 500° C. without entering a phase change; and
depositing a dielectric layer over said first semiconducting material.
38. The method of claim 37 , comprising depositing a silicon nitride layer on said silicon dioxide layer.
39. The method of claim 37 , comprising depositing a second semiconducting material between said first semiconducting material and said dielectric layer.
40. The method of claim 38 , comprising:
depositing a metallic or ohmic first contact on said silicon nitride layer; and
depositing a metallic or ohmic second contact positioned adjacent to at least said silicon nitride layer.
41. The method of claim 37 , wherein said substrate comprises sapphire, silicon, group III nitrides, or silicon carbide.
42. The method of claim 41 , comprising forming a diaphragm in said first semiconducting material by selectively etching an air gap in said substrate.
43. The high-temperature pressure sensor of claim 37 , wherein said substrate and first semiconducting material is etched to define a cantilever.
44. The high-temperature pressure sensor of claim 43 , wherein a diaphragm is attached to the cantilever to transmit pressure.