ELECTROMECHANICAL MONOLITHIC RESONATOR

• US 3,614,677 A
• Filed: 04/29/1966
• Issued: 10/19/1971
• Est. Priority Date: 04/29/1966
• Status: Expired due to Term

• Current Assignee: Raymond J. Wilfinger
• Original Assignee: Raymond J. Wilfinger
• Inventors: Wilfinger, Raymond J.
• Primary Examiner(s): Lake, Roy
• Assistant Examiner(s): Hostetter, Darwin R.
• Application Number:
  US04/546,310
• Time in Patent Office: 1,999 Days
• Field of Search: 317/235 333/71 310/4,4.1,25 331/156 34/1.5
• US Class Current: 333/200
• CPC Class Codes: H01L 27/00 Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate details thereof H01L23/00, H01L29/00 - H10K10/00; assemblies consisting of a plurality of individual solid state devices H01L25/00
• CPC Class Codes: H01L 29/00 Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor H01L31/00 - H01L33/00, H10K10/00, H10N take precedence; details other than of semiconductor bodies or of electrodes thereof H01L23/00; devices consisting of a plurality of solid state components formed in or on a common substrate H01L27/00
• CPC Class Codes: H03H 9/24 Constructional features of resonators of material which is not piezoelectric, electrostrictive, or magnetostrictive
• CPC Class Codes: H03H 9/46 Filters multiple-port electromechanical filters H03H9/70
• CPC Class Codes: H10N 39/00 Integrated devices, or assemblies of multiple devices, comprising at least one piezoelectric, electrostrictive or magnetostrictive element covered by groups H10N30/00 – H10N35/00

Abstract

A semiconductor substrate is supported so as to allow mechanical vibration of the substrate. This semiconductor substrate is of a size and has such electrical and mechanical characteristics as to be capable of sustaining mechanical stress and producing a useable resonance frequency. An excitation element is formed in the substrate at a suitable location to cause mechanical strain in the semiconductor substrate by a thermal expansion mechanism. The further addition of a device formed in the semiconductor substrate for converting mechanical stresses in the semiconductor substrate into electrical phenomena makes the semiconductor device of even greater value.

Claims

2. A device according to claim 1 in which the heating means comprises a semiconductor means attached to the member and electrical means for driving said semiconductor means.

3. A device according to claim 1 including means for abstracting an output from said member.

4. A device according to claim 3 in which the output-abstracting means comprises means for sensing changes in strain in the member.

5. A device according to claim 4 in which the member comprises an elongated member of semiconductive material, the heating means comprises a semiconductor means attached to the elongated member, and the output-abstracting means comprises a piezoresistive semiconductor diffused into said semiconductive material and provided with connections between which the resistance varies as a function of the strain in said material.

6. A device according to claim 1 in which the member comprises a reed of semiconductive material and nonresonant means for supporting said reed, and in which the heating means comprises a resistive element heat coupled to said reed and electrical means for driving resistive element to heat said reed, said device including means for coupling an output from said reed.

7. A device according to claim 6 in which the resistive element comprises a first semiconductor resistive element contacting the material of the reed and the output-coupling means comprises a second piezo resistive element contacting the material of said reed, both in orientations to undergo changes of resistivity as the strain of said reed changes.

8. A device according to claim 1 wherein said member comprises a substrate and said substrate is excited in a flexual mold.

9. A device according to claim 8 wherein said substrate is excited in a torsional mold.

10. A device according to claim 8 wherein said substrate is excited in an acoustical mode.

11. A device according to claim 1 wherein said member comprises a substrate and said means for heating comprises an electrical resistance element at the surface of said substrate.

12. A device according to claim 1 wherein said member comprises a substRate and said means for heating includes an electrical resistance established through the body of said substrate.

13. The device according to claim 1 wherein said member comprises a substrate and said means for heating includes a forward bias PN junction device in said substrate.

14. A device according to claim 1 wherein said member comprises a substrate and said means for a heating is a transistor device in said substrate operated to cause collector power dissipation.

15. A device according to claim 1 further including at least one piezoresistor sensor element.

16. A device according to claim 1 wherein said member comprises a substrate and further including more than one piezoresistor sensor element positioned in said substrate geometrically so as to cancel out thermal and electrical effect between said piezoresistors and the means for heating said substrate.

17. A device according to claim 1 further including at least one piezo PN junction sensor element.

18. A device according to claim 1 wherein said member comprises a substrate composed of a homopolar semiconductor material.

19. A device according to claim 18 wherein said means for heating and said sensor element are located on the periphery of said substrate substantially on a 45* spiral line.

20. A filter comprising an elongated member capable of flexing in response to a change in temperature and having a resonant frequency of flexing vibration, means for heating said member to change the temperature and produce flexure thereof, said heating means including input terminals to which may be applied a signal having a plurality of frequencies including said resonant frequency and including means coupled between said input terminals and said elongated member for converting said signal to heat, said elongated member and said heating means being mutually adapted to promote flexing vibration predominantly at said resonant frequency, and means for coupling from said elongated member a signal responsive to the portion of said signal at said resonant frequency.

21. A filter according to claim 20 in which the elongated member comprises a reed of semiconductive material, said filter including nonresonant means for supporting the elongated member and electrical means for applying the signal having a plurality of frequencies to said member.

22. A filter according to claim 21 in which the means for coupling a signal from the elongated member comprises an element of semiconductor resistive material diffused into said reed, and an output circuit connected across the element, said output circuit including means for biasing said element to carry a current responsive to changes in strain in said reed while not having a substantial effect in driving said reed.

23. A filter according to claim 21 in which the reed has two longitudinal regions and means separating said regions for providing a substantial degree of thermal isolation from one another, the heating means and the means for coupling the signal from the reed being disposed in different ones of said regions.

24. In an oscillator a device comprising a member capable of flexing in response to a change in temperature and having a resonant frequency of flexing vibration, and means for heating said member to change the temperature and produce flexure thereof, said member and said heating means being mutually adapted to promote flexing vibration predominantly at said resonant frequency.