Single-sided differential pressure sensor

Differential pressure sensor apparatus having a semiconductor structure and comprising

• A. a silicon substrate having a top surface and having a cavity recessing said top surface,
• B. a polysilicon diaphragm deposited over and secured to said substrate and spanning the cavity, said diaphragm having opposite top and bottom faces,
• C. a first pressure port mounted with said substrate and disposed for receiving a first fluid pressure from a first direction along a first axis,
• D. an opening through a deflecting portion of said diaphragm, said opening for communicating to the cavity a first fluid pressure applied to said first pressure port,
• E. a second pressure port mounted with said substrate and disposed for receiving a second fluid pressure from the first direction, said second pressure port being structured for applying the second fluid pressure to the span of the top face of said diaphragm over said cavity,
• F. electrical detection means for detecting the deflection of said diaphragm due to a pressure differential exerted across the diaphragm by the first and second fluid pressures,
• G. a housing mounting said pressure ports and said substrate and for directing the first fluid pressure to a first portion of the diaphragm proximal to the pressure passage and for directing the second fluid pressure to a second portion of the diaphragm distal to the pressure passage,
• wherein said housing means includes
• i. a carrier for mounting said substrate, and
• ii. a cap assembled with said carrier, said first and second pressure ports being mounted on said cap,
• whereby said first and second fluid pressures are applied to the same side of the pressure sensor apparatus and act substantially exclusively on different faces of said diaphragm.

Differential pressure sensor apparatus having a semiconductor structure and comprising

• A. a silicon substrate having a top surface and having a cavity recessing said top surface,
• B. a polysilicon diaphragm deposited over and secured to said substrate and spanning the cavity, said diaphragm having opposite top and bottom faces,
• C. a first pressure port mounted with said substrate and disposed for receiving a first fluid pressure from a first direction along a first axis,
• D. an opening through a deflecting portion of said diaphragm, said opening for communicating to the cavity a first fluid pressure applied to said first pressure port,
• E. a second pressure port mounted with said substrate and disposed for receiving a second fluid pressure from the first direction, said second pressure port being structured for applying the second fluid pressure to the span of the top face of said diaphragm over said cavity,
• F. electrical detection means for detecting the deflection of said diaphragm due to a pressure differential exerted across the diaphragm by the first and second fluid pressures,
• G. means forming a first chamber proximal to the pressure passage and forming a second chamber distal to the pressure passage,
• whereby said first and second fluid pressures are applied to the same side of the pressure sensor apparatus and act substantially exclusively on different faces of said diaphragm.