SOI diaphragm sensor
AssigneeKopin Corporation
InventorsPaul M. Zavracky, Richard H. Morrison, Jr.
Life of this patent
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Abstract
The present invention relates to the fabrication of diaphragm pressure sensors utilizing silicon-on-insulator technology where recrystallized silicon forms a diaphragm which incorporates electronic devices used in monitoring pressure. The diaphragm is alternatively comprised of a silicon nitride having the necessary mechanical properties with a recrystallized silicon layer positioned thereon to provide sensor electronics.
Claims30
A self-calibrated sensor comprising:
- a substrate of semiconductor material;
- a layer of sacrificial material formed on the substrate;
- a sensor structure formed with a layer of epitaxial semiconductor material positioned over the layer of sacrificial material;
- and
- a calibration circuit formed in the layer of epitaxial semiconductor material to calibrate the sensor.
A microsensor comprising:
- a substrate of semiconductor material;
- a layer of sacrificial material deposited on the substrate;
- a sensor structure formed in a layer of epitaxial semiconductor material positioned over the layer of sacrificial material;
- and
- a monitoring circuit formed on the layer of epitaxial semiconductor material that determines whether an additional circuit in the sensor is shorted or whether another circuit in the sensor is open.
A microsensor comprising:
- a substrate of semiconductor material;
- a layer of sacrificial material formed on the substrate;
- a sensor structure formed in the layer of sacrificial material;
- and
- a calibration circuit formed in the layer of epitaxial silicon that compensates for a non-linear characteristic of the sensor.
An integrated circuit comprising:
- a substrate of silicon;
- a layer of electrically insulating material;
- a plurality of redundant sensor structures formed out of a layer of silicon nitride deposited on the layer of electrically insulating material such that if one sensor structure fails, another redundant sensor structure replaces the failed sensor;
- and
- an electrical circuit formed on the layer of epitaxial silicon nitride.
A method of forming a semiconductor diaphragm pressure sensor comprising:
- forming an electrically insulating layer portion on a semiconductor substrate;
- forming a polycrystalline semiconductor layer over the substrate that encloses the insulating layer portion between the semiconductor and the substrate;
- recrystallizing the polycrystalline layer to form a substantially single crystal flexible member;
- integrating an electronic circuit into the single crystal member;
- opening a portion of the single crystal member to expose a surface portion of the insulating portion;
- removing the enclosed insulating portion through the opened portion;
- and
- sealing the opened portion of the single crystal member.
A method of forming semiconductor diaphragm pressure sensor comprising:
- forming an insulating layer portion on a semiconductor substrate;
- forming a silicon nitride layer over the substrate such that the insulating portion is enclosed between the nitride layer and the substrate;
- forming a polycrystalline silicon layer over the silicon nitride layer;
- recrystallizing the polycrystalline layer to form a substantially single crystal silicon layer;
- integrating an electronic circuit into the crystal silicon layer;
- opening a portion of the silicon nitride layer to expose a surface portion of the insulating portion;
- and
- removing the insulation portion through the opened portion to form a silicon nitride diaphragm.
A differential semiconductor pressure sensor comprising:
- a substrate of polysilicon;
- a first layer of electrically insulating, material deposited on the substrate;
- an epitaxial silicon diaphragm formed on top of the first layer of electrically insulating material;
- a second layer of electrically insulating material deposited over the epitaxial silicon diaphragm;
- a polysilicon nitride film to cap the sensor;
- a lower cavity formed in the substrate below the diaphragm and first electrically insulating layer;
- and
- an upper cavity formed in the polysilicon nitride film above the diaphragm and second electrically insulating layer.
Dependencies are inferred from the claim text.