Method and apparatus for switching high frequency signals

• US 20020036304A1
• Filed: 12/04/2001
• Published: 03/28/2002
• Est. Priority Date: 11/25/1998
• Status: Active Grant

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Yao, Zhimin J., Eshelman, Susan M., Ehmke, John C., Goldsmith, Charles L.
• Granted Patent: US 6,700,172 B2
• Time in Patent Office: Days
• US Class Current: 257/254
• 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 switch comprising:

a conductive region;

a membrane;

a dielectric region formed from a dielectric material, the dielectric region disposed between the membrane and the conductive region;

wherein a sufficient voltage applied between the conductive region and the membrane effects a capacitive coupling between the membrane and the conductive region; and

wherein the dielectric material has a resistivity sufficiently low to inhibit charge accumulation in the dielectric region during operation of the switch.

2. The switch of claim 1, wherein the dielectric material further has a resistivity sufficiently low to generally prevent bipolar operation of the switch.

3. The switch of claim 1, wherein the dielectric material further has a resistivity sufficiently low to generally prevent release of the capacitive coupling while the sufficient voltage is applied.

4. The switch of claim 1, wherein the dielectric material has a resistivity less than approximately 1×

10¹¹ ohm-cm measured in an electric field of approximately 200 kV/cm.

5. The switch of claim 1, wherein the dielectric material comprises silicon nitride having a resistivity less than approximately 1×

10¹¹ ohm-cm measured in an electric field of approximately 200 kV/cm.

6. The switch of claim 1, wherein the dielectric material comprises silicon nitride having a resistivity of approximately 1×

10⁷ ohm-cm measured at approximately 200 kV/cm.

7. The switch of claim 1, wherein the dielectric material further has 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.