Method for making an all-silicon capacitive pressure sensor
US5706565A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 3, 1996 |
| Grant date | Jan 13, 1998 |
| Priority date | — |
| Expiry date | Sep 3, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/435
- 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.