Systems, devices, and methods for reducing surface dielectric charging in a RF MEMS actuator element

• US 10,640,362 B2
• Filed: 04/01/2015
• Issued: 05/05/2020
• Est. Priority Date: 04/01/2014
• Status: Active Grant

• Current Assignee: AAC Technologies Pte Limited (AAC Technologies Holdings Inc.)
• Original Assignee: WiSpry, Inc (AAC Technologies Holdings Inc.)
• Inventors: Molinero-Giles, David, Cunningham, Shawn J., DeReus, Dana
• Primary Examiner(s): Hollington, Jermele M
• Assistant Examiner(s): Singh, Alexander A
• Application Number:
  US14/676,488
• Publication Number:
  US 20150279602A1
• Time in Patent Office: 1,861 Days
• CPC Class Codes: B81B 2203/04 Electrodes
• CPC Class Codes: B81B 3/0008 Structures for avoiding electrostatic attraction, e.g. avoiding charge accumulation
• CPC Class Codes: B81B 3/001 Structures having a reduced contact area, e.g. with bumps or with a textured surface
• CPC Class Codes: B81B 3/0086 Electrical characteristics, e.g. reducing driving voltage, improving resistance to peak voltage
• 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 2059/0072 with stoppers or protrusions for maintaining a gap, reducing the contact area or for preventing stiction between the movable and the fixed electrode in the attracted position
• CPC Class Codes: H01H 59/0009 making use of micromechanics

Abstract

The present subject matter relates to systems, devices, and methods for reducing surface dielectric charging in a RF MEMS actuator element. In particular, a micro-electro-mechanical systems (MEMS) can comprise a fixed electrode positioned on a substrate, a moveable electrode positioned substantially above the fixed electrode and separated from the fixed electrode by a gap, and at least one standoff bump positioned between the fixed electrode and the moveable electrode, wherein the at least one standoff bump extends into the gap. In this configuration, one or both of the fixed electrode or the moveable electrode can be patterned to define one or more hole that is substantially aligned with the one or more of the at least one standoff bump. The bump and the hole can both help to reduce the rate of surface dielectric charging and the total amount of charge generated.

Claims

1. A micro-electro-mechanical systems (MEMS) component comprising:

a fixed electrode positioned on a substrate;

a moveable electrode positioned substantially above the fixed electrode and separated from the fixed electrode by a gap; and

at least one standoff bump positioned between the fixed electrode and the moveable electrode, wherein the at least one standoff bump extends into the gap;

wherein one or both of the fixed electrode or the moveable electrode is patterned to define one or more hole that is substantially aligned with the one or more of the at least one standoff bump; and

wherein the one or more hole extends beyond all edges of the at least one standoff bump such that a distance between an edge of the hole and a respective edge of the at least one standoff bump is greater than or about equal to a height of the at least one standoff bump and less than or about equal to a maximum gap spacing between the fixed electrode and the movable electrode.

2. The micro-electro-mechanical systems (MEMS) component of claim 1, wherein the at least one standoff bump comprises a plurality of standoff bumps arranged in a spaced-apart arrangement between the fixed electrode and the moveable electrode.

3. The micro-electro-mechanical systems (MEMS) component of claim 2, wherein the spaced-apart arrangement comprises the plurality of standoff bumps being arranged in an array.

4. The micro-electro-mechanical systems (MEMS) component of claim 1, wherein the hole in one or both of the fixed electrode or the moveable electrode has a dimension that is larger than three times a width of the at least one standoff bump.

5. The micro-electro-mechanical systems (MEMS) component of claim 1, comprising one or more fixed dielectric material layers positioned on the fixed electrode between the fixed electrode and the movable electrode.

6. The micro-electro-mechanical systems (MEMS) component of claim 5, wherein the at least one standoff bump is connected to the one or more fixed dielectric material layers.

7. The micro-electro-mechanical systems (MEMS) component of claim 1, comprising one or more movable dielectric material layers attached to the movable electrode between the fixed electrode and the movable electrode.

8. The micro-electro-mechanical systems (MEMS) component of claim 7, wherein the at least one standoff bump is connected to the one or more movable dielectric material layers.

9. A micro-electro-mechanical systems (MEMS) component comprising:

a fixed electrode positioned on a substrate;

a moveable electrode positioned substantially above the fixed electrode and separated from the fixed electrode by a gap; and

at least one standoff bump positioned between the fixed electrode and the moveable electrode, wherein the at least one standoff bump extends into the gap;

wherein the moveable electrode is patterned to define one or more hole that is substantially aligned with one or more of the at least one standoff bump, the hole having a dimension that is larger than a width of the at least one standoff bump but smaller than a maximum gap spacing between the fixed electrode and the movable electrode; and

wherein an amount that the one or more hole extends beyond a periphery of the at least one standoff bump is significantly larger than a minimum gap spacing between the fixed electrode and the movable electrode.

10. The micro-electro-mechanical systems (MEMS) component of claim 9, wherein the at least one standoff bump comprises a plurality of standoff bumps arranged in a spaced-apart arrangement between the fixed electrode and the moveable electrode.

11. The micro-electro-mechanical systems (MEMS) component of claim 9, comprising one or more fixed dielectric material layers positioned on the fixed electrode between the fixed electrode and the movable electrode.

12. The micro-electro-mechanical systems (MEMS) component of claim 11, wherein the at least one standoff bump is connected to the one or more fixed dielectric material layers.

13. The micro-electro-mechanical systems (MEMS) component of claim 9, comprising one or more movable dielectric material layers attached to the movable electrode between the fixed electrode and the movable electrode.

14. The micro-electro-mechanical systems (MEMS) component of claim 13, wherein the at least one standoff bump is connected to the one or more movable dielectric material layers.

15. The micro-electro-mechanical systems (MEMS) component of claim 9, wherein the hole in the moveable electrode has a dimension that is larger than three times a width of the at least one standoff bump.

16. A method for forming a micro-electro-mechanical systems (MEMS) component, the method comprising:

depositing a fixed electrode on a substrate;

depositing a sacrificial layer over the fixed electrode;

etching the sacrificial layer to define at least one standoff cavity over the fixed electrode;

depositing one or more movable dielectric layers over the sacrificial layer, wherein at least one standoff bump is defined in the at least one standoff cavity;

depositing a movable electrode over the one or more movable dielectric layers;

etching the movable electrode to define one or more hole that is substantially aligned with one or more of the at least one standoff bump; and

removing the sacrificial layer such that the one or more movable dielectric layers and the movable electrode are spaced apart from the fixed electrode by a gap;

wherein an amount that the one or more hole extends beyond a periphery of the at least one standoff bump is significantly larger than a minimum gap spacing between the fixed electrode and the movable electrode.

17. The method of claim 16, wherein etching the movable electrode to define one or more hole comprises etching the movable electrode to define one or more hole having a dimension that is smaller than a maximum gap spacing between the fixed electrode and the movable electrode after removing the sacrificial layer.

18. The method of claim 16, wherein etching the movable electrode to define one or more hole comprises etching the movable electrode to define a plurality of holes in a spaced-apart arrangement over the fixed electrode.

19. The method of claim 16, comprising depositing one or more fixed dielectric layers over the fixed electrode prior to depositing the sacrificial layer.

20. The method of claim 16, comprising depositing one or more additional movable dielectric layer to substantially fill the one or more hole.

21. The method of claim 16, wherein the hole in the moveable electrode has a dimension that is larger than three times a width of the at least one standoff bump.