Solid state microanemometer with improved sensitivity and response time
First Claim
1. A solid state microanemometer comprising:
- a non-conductive base having a top surface;
four semiconductor supports located above said top surface; and
a Wheatstone bridge comprising four semiconductor resistor legs interconnected in a substantially common plane to four electrically conductive contacts located on top of said four supports, said common plane being at a predetermined distance above said top surface, thereby to substantially thermally isolate said resistors from said base and said supports.
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Accused Products
Abstract
A solid state microanemometer with improved sensitivity and response time is micromachined out of a single deep level doped semiconductor crystal and includes four corner supports interconnected to four spanning members which form the resistor legs of a Wheatstone bridge. The bottom of the supports are electrostatically bonded to a glass plate, thus thermally isolating the resistor legs a predetermined distance above the top surface of the plate and electrically isolating the supports. Electrically conductive material deposited on the four corner supports provides electrical contacts which enable a voltage to be applied across the resistor legs. Preferably, an n+ material is diffused into the region of the crystal located beneath the electrically conductive material, and the exposed surfaces of the crystal are sealed with a passivation layer.
31 Citations
39 Claims
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1. A solid state microanemometer comprising:
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a non-conductive base having a top surface; four semiconductor supports located above said top surface; and a Wheatstone bridge comprising four semiconductor resistor legs interconnected in a substantially common plane to four electrically conductive contacts located on top of said four supports, said common plane being at a predetermined distance above said top surface, thereby to substantially thermally isolate said resistors from said base and said supports. - View Dependent Claims (2, 3, 8, 9, 10, 11, 12, 13, 14, 17)
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- 4. The microanemometer of claim wherein said resistor legs comprise a semiconductor material doped with a deep level impurity.
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18. A solid state microanemometer comprising:
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a borosilicate base having a top surface; a deep level doped semiconductor crystal having top and bottom etched surfaces, the etched surfaces defining four corner supports interconnected by four spanning members, the supports being electrostatically bonded to said top surface to place said spanning members a predetermined distance above said top surface; four electrically conductive contacts located substantially on top of said corner supports for applying a voltage across each of said spanning members. - View Dependent Claims (19, 20, 21, 22, 23, 24)
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25. A method of forming a solid state microanemometer out of a single crystal comprising the steps of:
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etching a backside surface of said crystal to provide four supports; bonding said supports to a base; etching a frontside surface of said bonded crystal to provide four spanning members interconnecting said supports, said spanning members being located a predetermined distance above said base; and depositing electrically conductive contact material on top of said supports. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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36. A solid state microanemometer comprising:
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a non-conductive base having a top surface; four semiconductor supports located above said top surface; and a Wheatstone bridge comprising four semiconductor resistor legs interconnected to four electrically conductive contacts located on top of said four supports, each of said supports being electrically isolated from the other said supports and said resistor legs. - View Dependent Claims (37, 38, 39)
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Specification