Gas pressure sensor based on short-distance heat conduction and method for fabricating same
First Claim
1. A pressure sensor comprising:
- a substrate;
a member having a portion adherent by stiction to a surface of the substrate, means for heating the portion of the member; and
means for monitoring a temperature of the portion of the member, the means for monitoring a temperature of the portion of the member controlling an output signal to indicate a pressure of a gas to which the pressure sensor is exposed.
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Accused Products
Abstract
A thermal pressure sensor monitors pressure by measuring effects caused by variations of thermal conductivity between a member and a substrate to which the member is adhered by stiction. The interface between the member and the substrate behaves as an extremely narrow gap. In a preferred embodiment the member is a bridge extending between a pair of cantilever arms. Two pressure sensors may be combined in a Wheatstone bridge configuration. A method for fabricating a pressure sensor according to the invention comprises forming a layer of oxide on a substrate, depositing a layer of material on the oxide layer, forming the member from the layer of material, removing the oxide layer and then bringing the member into contact with the substrate. The portion of the substrate under the member may be patterned with plateaus and valleys.
20 Citations
33 Claims
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1. A pressure sensor comprising:
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a substrate;
a member having a portion adherent by stiction to a surface of the substrate, means for heating the portion of the member; and
means for monitoring a temperature of the portion of the member, the means for monitoring a temperature of the portion of the member controlling an output signal to indicate a pressure of a gas to which the pressure sensor is exposed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 18)
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11. A pressure sensor comprising:
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a substrate;
a member adherent by stiction to a surface of the substrate, means for heating the member; and
means for monitoring a temperature of the member, the means for monitoring a temperature of the member controlling an output signal to indicate a pressure of a gas to which the pressure sensor is exposed;
wherein the member comprises a generally linear elongated bridge supported above the substrate at either end, the bridge having a central portion collapsed onto and adhering by stiction to the surface of the substrate.
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19. A composite pressure sensor comprising first and second pressure sensors the first and second pressure sensors each comprising:
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a substrate;
a member adherent by stiction to a surface of the substrate, means for heating the member; and
means for monitoring a temperature of the member, the means for monitoring a temperature of the member controlling an output signal to indicate a pressure of a gas to which the pressure sensor is exposed;
the pressure sensors arranged with first and second resistors in a Wheatstone bridge configuration having first and second output points and first and second input points, the means for monitoring a temperature of the member of the first pressur sensor connected between the first input point and the first output point, the means for monitoring a temperature of the member of the second pressure sensor connected between the second input point and the second output point, the first resistor connected between the first input point and the second output and the second resistor connected between the second input point and the first output point. - View Dependent Claims (20, 21)
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- 22. A pressure sensor comprising a substrate, a member having a portion adherent by stiction to a surface of the substrate, a heater located to heat the portion of the member and a temperature sensor located to generate a signal responsive to a temperature of the portion of the member, the signal indicative of a pressure of a gas to which the pressure sensor is exposed.
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32. A pressure sensor comprising a substrate, a member adherent by stiction to a surface of the substrate, a heater located to heat the member and a temperature sensor located to generate a signal responsive to a temperature of the member, the signal indicative of a pressure of a gas to which the pressure sensor is exposed wherein the member comprises a generally linear elongated bridge supported above the substrate at either end, the bridge having a central portion collapsed onto and adhering by stiction to a surface of the substrate.
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33. A composite pressure sensor comprising first and second pressure sensors arranged with first and second resistors in a Wheatstone bridge configuration having first and second output points and first and second input points, each of the pressure sensors comprising a substrate, a member adherent by stiction to a surface of the substrate, a heater located to heat the member and a temperature sensor located to generate a signal responsive to a temperature of the member the signal indicative of a pressure of a gas to which the pressure sensor is exposed the temperature sensor of the first pressure sensor connected between the first input point and the first output point, the temperature sensor of the second pressure sensor connected between the second input point and the second output point, the first resistor connected between the first input point and the second output point and the second resistor connected between the second input point and the first output point.
Specification