Integrated single crystal pressure transducer

• US 3,916,365 A
• Filed: 09/28/1973
• Issued: 10/28/1975
• Est. Priority Date: 01/31/1972
• Status: Expired due to Term

• Current Assignee: Elsag International NV
• Original Assignee: Joseph M. Giachino
• Inventors: Giachino, Joseph M.
• Primary Examiner(s): Albritton, C. L.
• Application Number:
  US05/401,759
• Time in Patent Office: 760 Days
• Field of Search: 338/2-6 73/88.5SD 148/175 117/234M,106 29/620 357/26,80
• US Class Current: 338/2
• CPC Class Codes: G01L 9/0055 bonded on a diaphragm

Abstract

A single crystal piezoresistive material is epitaxially grown on a single crystal dielectric substrate. The piezoresistive material is then selectively removed from the substrate to form a crystallographically oriented sensor in conjunction with the substrate, which sensor changes resistance in response to pressure applied to the substrate. An integrated single crystal transducer is produced thereby with the sensor element electrically isolated by the dielectric substrate.

Claims

1. An integrated single crystal pressure transducer, comprising:

a substrate of single crystaL dielectric material;

a single crystal piezoresistive material epitaxially grown on said substrate to form an integrated single crystal with said substrate; and

said piezoresistive material occurring at regions of said substrate sensitive to the stress, whether tensive or compressive, caused by pressure applied thereto as a function of location on the substrate and the geometry thereof in order that said piezoresistive material mechanically and electrically responds to pressure applied to said integrated crystal.

2. An integrated single crystal pressure transducer as set forth in claim 1;

wherein said substrate is a cube having substantially identical dimension faces to produce a substantially identical electrical response from said transducer upon application of a pressure to any of the faces of said cube perpendicular to said piezoresistive material pattern.

3. An integrated single crystal pressure transducer as set forth in claim 1;

including transducer signal modifying means, bonded to said substrate and electrically coupled to the piezoresistive material for enhancing the output suitability of said transducer signal and wherein said piezoresistive material is a doped silicon.

4. An integrated single crystal pressure transducer as set forth in claim 1;

wherein said peizoresistive material occurs on said substrate in the form of first and second perpendicular strips, said strips being aligned with respect to said substrate so that said first strip is electrically insensitive to pressure applied to said crystal and said second strip is electrically sensitive to pressure applied to said crystal.

5. An integrated single crystal pressure transducer as set forth in claim 4;

wherein said first and second strips are of substantially equal resistance prior to a differential in pressure being applied to different faces of said crystal.

6. An integrated single crystal pressure transducer as set forth in claim 5;

wherein said piezoresistive material is grown on a face of said substrate defined by the (1,1,1) crystallographic orientation.

7. An integrated single crystal pressure transducer as set forth in claim 6;

wherein said substrate of dielectric material is spinel.

8. An integrated single crystal pressure transducer as set forth in claim 2, wherein said piezoresistive material pattern comprises a first piezoresistive strip and a second piezoresistive strip aligned with said substrate so that one of said strips is electrically insensitive to pressure applied to said substrate and the other of said strips is electrically sensitive to pressure applied to said substrate and wherein said strips are of substantially equal resistance prior to pressure being applied to said substrate.