High sensitivity micro-machined pressure sensors and acoustic transducers
AssigneeNational Semiconductor Corporation
InventorsRashid Bashir, Abul Kabir
Life of this patent
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Abstract
A method of making a pressure sensor or acoustic transducer having high sensitivity and reduced size. A thin sensing diaphragm is produced by growing a single crystal, highly doped silicon layer on a substrate using a chemical vapor deposition process. The diaphragm is incorporated into a pressure sensor or acoustic transducer which detects pressure variations by a change in the capacitance of a capacitor which includes the diaphragm as a movable member. The thin diaphragm produces a highly sensitive device which can be fabricated in a smaller size than sensors or transducers having thicker diaphragms.
Claims7
An acoustic transducer or pressure sensor, comprising:
- a substrate having a top surface and a bottom surface;
- a single crystal silicon diaphragm formed on the top surface of the substrate, the diaphragm having a thickness of one micron or less;
- an aperture formed in the bottom surface of the substrate and extending to the diaphragm;
- and
- a contact electrically connected to the diaphragm, the contact located on the top surface of the substrate and electrically isolated from the substrate.
Dependencies are inferred from the claim text.