Semiconductive structure useful as a pressure sensor
First Claim
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1. A pressure sensor comprising:
- a monocrystalline semiconductive chip including within its bulk a sealed buried cavity whose lateral extent defines a surface of an overlying diaphragm layer which includes an epitaxial moncrystalline portion and which extends to a first surface of the chip;
means forming at least one strain gage in a portion of the diaphragm layer; and
means in said surface surrounding the diaphragm layer for forming circuit elements for interconnection with said strain gage(s).
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Abstract
A pressure sensor uses a monocrystalline silicon chip that has a diaphragm portion in which strain gages are formed that overlie a buried cavity. The cavity is formed by a single sided semiconductor fabrication process that includes a pair of preferential etching steps and an epitaxial deposition step.
74 Citations
3 Claims
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1. A pressure sensor comprising:
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a monocrystalline semiconductive chip including within its bulk a sealed buried cavity whose lateral extent defines a surface of an overlying diaphragm layer which includes an epitaxial moncrystalline portion and which extends to a first surface of the chip; means forming at least one strain gage in a portion of the diaphragm layer; and means in said surface surrounding the diaphragm layer for forming circuit elements for interconnection with said strain gage(s).
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2. A semiconductive structure comprising:
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a monocrystalline silicon chip including within its bulk an enclosed buried cavity whose lateral extent defines a surface of an overlying monocrystalline silicon diaphragm which includes an epitaxial monocrystalline silicon portion sealing the cavity, and which extends to a first surface of the chip; means forming four piezoresistors in a portion of the diaphragm layer and interconnecting them to form a Wheatstone bridge; and means in said chip surrounding said diaphragm layer for forming circuit elements for interconnection with the Wheatstone bridge.
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3. A semiconductive pressure sensor structure comprising:
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a monocrystalline silicon chip including within its bulk an enclosed buried cavity whose lateral extent defines a surface of an overlying silicon diaphragm layer, said diaphragm layer including an epitaxial monocrystalline silicon portion which seals said enclosed cavity, and said diaphragm layer extending to a first surface of the chip; means forming at least one pressure sensitive device in a portion of the diaphragm layer; and means in said surface surrounding the diaphragm layer for forming circuit elements for interconnection with the pressure sensitive device.
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Specification