Method and apparatus for switching high frequency signals

• US 6,391,675 B1
• Filed: 09/13/1999
• Issued: 05/21/2002
• Est. Priority Date: 11/25/1998
• Status: Expired due to Term

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Ehmke, John C., Yao, Zhimin J., Goldsmith, Charles L., Eshelman, Susan M.
• Primary Examiner(s): Whitehead, Jr., Carl
• Assistant Examiner(s): VOCKRODT, JEFF B
• Application Number:
  US09/394,997
• Time in Patent Office: 981 Days
• Field of Search: 438/50, 438/52, 438/53, 307/109, 335/35, 333/151, 333/154
• US Class Current: 438/53
• CPC Class Codes: H01G 5/16 using variation of distance between electrodes
• CPC Class Codes: H01G 5/40 Structural combinations of variable capacitors with other electric elements not covered by this subclass, the structure mainly consisting of a capacitor, e.g. RC combinations
• CPC Class Codes: H01H 2059/0018 Special provisions for avoiding charge trapping, e.g. insulation layer between actuating electrodes being permanently polarised by charge trapping so that actuating or release voltage is altered
• CPC Class Codes: H01H 59/0009 making use of micromechanics
• CPC Class Codes: H01P 1/127 Strip line switches

Abstract

A switch includes a conductive region, a membrane, and a dielectric region. The dielectric region is formed from a dielectric material and is disposed between the membrane and the conductive region. When a sufficient voltage is applied between the conductive region and the membrane, a capacitive coupling between the membrane and the conductive region is effected. The dielectric material has a resistivity sufficiently low to inhibit charge accumulation in the dielectric region during operation of the switch.

Claims

1. A method of forming a switch, the method comprising:

providing a conductive region;

providing a membrane;

providing a dielectric material;

disposing a region of the dielectric material between the conductive region and the membrane such that a sufficient voltage applied between the conductive region and the membrane effects a capacitive coupling between the membrane and the conductive region; and

wherein providing the dielectric material comprises providing a dielectric material having a resistivity of no greater than approximately 1×

10⁷ ohm-cm.

2. The method of claim 1 wherein providing the dielectric material comprises providing a dielectric material having a resistivity sufficiently low to generally prevent bipolar operation of the switch.

3. The method of claim 1 wherein providing the dielectric material comprises providing a dielectric material having a resistivity sufficiently low to generally prevent release of the capacitive coupling while the sufficient voltage is applied.

8. The method of claim 1, wherein the resistivity of the dielectric material is approximately 1×

10⁷ ohm-cm.

10. The method of claim 1, wherein the dielectric material is silicon nitride.

4. A method of forming a capacitive switch, the method comprising:

providing a substrate;

disposing a conductive region overlying the substrate;

disposing a dielectric region overlying the conductive region;

disposing a membrane over the dielectric region such that a sufficient voltage applied between the conductive region and the membrane effects a capacitive coupling between the membrane and the conductive region; and

wherein disposing a dielectric region overlying the conductive region comprises providing a dielectric material having a resistivity that is no greater than approximately 1×

10⁷ ohm-cm.

5. The method of claim 4 wherein providing the dielectric material comprises providing a dielectric material having a resistivity sufficiently low to generally prevent bipolar operation of the switch.

6. The method of claim 4 wherein providing the dielectric material comprises providing a dielectric material having a resistivity sufficiently low to generally prevent release of the capacitive coupling while the sufficient voltage is applied.

7. The method of claim 4, wherein providing a dielectric material comprises providing a dielectric material having a resistivity sufficiently low to generally prevent bipolar operation of the switch and sufficiently low to generally prevent release of the capacitive coupling while the sufficient voltage is applied.

9. The method of claim 4, wherein the resistivity of the dielectric material is approximately 1×

10⁷ ohm-cm.

11. The method of claim 4, wherein the dielectric material is silicon nitride.