Static and dynamic pressure sensor
View Patent ↗A sensor, in accordance with aspects of the present technique, is provided. The sensor comprises a membrane formed of gallium nitride. The membrane is disposed on a substrate, which is wet-etched to form a closed cavity. The membrane exhibits both a capacitive response and a piezo-response to an external stimulus. The sensor further includes a circuit for measuring at least one of the capacitive response or the piezo-response. In certain aspects, the sensor may be operable to measure external stimuli, such as, pressure, force and mechanical vibration.
1. A sensor, comprising:
a membrane formed of gallium nitride;
a sapphire substrate that has been wet-etched to form a cavity, wherein the membrane is disposed on said sapphire substrate and exhibits both a capacitive response and a piezo-response to an external stimulus, wherein the membrane is coupled to and bound by the substrate; and
a circuit for measuring at least one of the capacitive response or the piezo-response.
2. The sensor as recited in claim 1 , wherein the membrane comprises at least one diaphragm.
3. The sensor as recited in claim 1 , wherein the sensor is operable at temperature in excess of about 200 degree Celsius.
4. The sensor as recited in claim 1 , further comprising a substrate formed of silicon carbide.
5. The sensor as recited in claim 1 , wherein the membrane provides a response to pressure.
6. The sensor as recited in claim 1 , wherein the membrane provides a response to force.
7. The sensor as recited in claim 1 , wherein the membrane provides a response to mechanical vibration.
8. A sensor, comprising:
a membrane formed of gallium nitride;
a sapphire substrate that has been wet-etched to form a cavity, wherein said membrane is disposed on said sapphire substrate, wherein said membrane is coupled to and bound by said substrate; and
an optical mechanism configured to measure a deflection of the membrane in response to an external stimulus.
9. The sensor of claim 8 , wherein the membrane comprises at least one diaphragm.
10. The sensor as recited in claim 8 , wherein the sensor is operable at temperature in excess of about 200 degree Celsius.
11. The sensor as recited in claim 8 , further comprising a substrate formed of silicon carbide.
12. The sensor as recited in claim 8 , wherein the external stimulus comprises pressure.
13. The sensor as recited in claim 8 , wherein the external stimulus comprises force.
14. The sensor as recited in claim 8 , wherein the external stimulus comprises mechanical vibration.
15. A pressure sensor comprising a gallium nitride membrane, wherein the pressure sensor is formed by:
etching a sapphire substrate disposed with the gallium nitride membrane to form a cavity, the gallium nitride membrane being coupled to and bound by the sapphire substrate and being operable to respond to at least one of a piezo-response, a capacitive response, an optical interrogation, or an external stimulus; and
coupling a circuit that measures at least one of the piezo-response, the capacitive response, or the optical interrogation.
16. The pressure sensor of claim 15 , wherein etching the substrate disposed with the gallium nitride membrane comprises wet-etching the substrate via cryolite.