All-silicon capacitive pressure sensor
US5936164A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 27, 1997 |
| Grant date | Aug 10, 1999 |
| Priority date | — |
| Expiry date | Aug 27, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L9/0073
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An all-silicon monolithic capacitive absolute pressure-sensing device and method for making the same. The device employs a single-crystal silicon diaphragm that serves at a flexible capacitor plate of a variable capacitor. The diaphragm is bonded to a single-crystal silicon wafer to overlie a cavity etched into the wafer. A fixed capacitor plate of the variable capacitor is formed by a heavily-doped region at the bottom of the cavity. A thin dielectric layer is grown on the fixed capacitor plate to complete the capacitor. The cavity has a minimal depth such that the fixed capacitor plate provides overpressure protection for the diaphragm. At least a portion of the operating range of the pressure sensor occurs while the diaphragm is contacting the doped region. As a result, the capacitive output signal of the pressure sensor is produced by changes in contact area between the diaphragm and a thin dielectric situated on the doped region in response to pressure applied to the diaphragm.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.