Silicon strain gage having a thin layer of highly conductive silicon

• US 6,635,910 B1
• Filed: 07/22/1999
• Issued: 10/21/2003
• Est. Priority Date: 07/22/1999
• Status: Expired due to Term

• Current Assignee: Measurement Specialties Incorporated (TE Connectivity Limited)
• Original Assignee: Measurement Specialties Incorporated (TE Connectivity Limited)
• Inventors: Gross, Chris
• Primary Examiner(s): Abraham, Fetsum
• Application Number:
  US09/359,012
• Time in Patent Office: 1,552 Days
• Field of Search: 257/254, 257/415, 257/417, 338/2
• US Class Current: 257/254
• CPC Class Codes: G01L 1/18 using properties of piezo-resistive materials, i.e. materials of which the ohmic resistance varies according to changes in magnitude or direction of force applied to the material
• CPC Class Codes: G01L 1/2293 of the semi-conductor type semi-conductor devices controllable by variations of applied mechanical force H01L29/84

Abstract

A semiconductor strain gage having an electrically resistive substrate layer and a layer of electrically conductive silicon supported by the substrate layer. The silicon layer can be an epitaxial silicon layer grown on a surface of the substrate layer or a diffused or ion-implanted layer formed in the surface of the substrate layer. Also, a force measuring and detecting device including a force responsive member and the above-described semiconductor strain gage attached to the force responsive member, the strain gage measuring forces applied to the force responsive member.

Claims

1. A force measuring and detecting device comprising:

a force responsive member; and

a semiconductor strain gage attached to the force responsive member, the strain gage measuring forces applied to the force responsive member, the strain gage including an electrically resistive substrate layer and a layer of electrically conductive silicon disposed on the substrate layer, wherein the substrate layer has a thickness of about 8-10 microns.

2. The device according to claim 1, wherein the force responsive member is metallic.

3. The device according to claim 1, wherein the substrate layer is composed of one of a semi-insulating material and an insulating material.

4. The device according to claim 3, wherein the semi-insulating material is silicon and the insulating material is alumina.

5. The device according to claim 1, wherein the substrate layer has a resistivity of greater than 10 ohm-cm.

6. The device according to claim 1, wherein the silicon layer is composed of epitaxial silicon.

7. The device according to claim 6, wherein the epitaxial silicon has a thickness of about 2-microns.

8. The device according to claim 1, wherein the silicon layer has a resistivity of about 0.025-0.060 ohm-cm.

9. The device according to claim 2, wherein the substrate layer is glass bonded to the force responsive member.

10. The device according to claim 1, wherein the substrate layer is glass bonded to the force responsive member.

11. The device according to claim 1, wherein the silicon layer is a diffused layer.

12. The device according to claim 1, wherein the silicon layer is an ion-implanted layer.