Patent Issued for RF MEMS Electrodes With Limited Grain Growth (USPTO 10,301,173)

Chemicals & Chemistry Business Daily |

2019 JUN 12 (NewsRx) -- By a News Reporter-Staff News Editor at Chemicals & Chemistry Business Daily Business Daily Daily -- According to news reporting originating from Alexandria, Virginia, by NewsRx journalists, a patent by the inventor Renault, Mickael (San Jose, CA), filed on , was published online on .

The assignee for this patent, patent number 10,301,173, is Cavendish Kinetics Inc. (San Jose, California, United States).

Reporters obtained the following quote from the background information supplied by the inventors: “Field of the Invention

“Embodiments of the present invention generally relate to a RF micro electromechanical system (MEMS) digital variable capacitor (DVC) and methods for manufacture thereof.

“Description of the Related Art”

In addition to obtaining background information on this patent, NewsRx editors also obtained the inventor’s summary information for this patent: “The present invention generally relates to an RF MEMS DVC and a method for manufacture thereof. To ensure that undesired grain growth does not occur and contribute to an uneven RF electrode, a multilayer stack comprising an AlCu layer and a layer containing titanium may be used. The titanium diffuses into the AlCu layer at higher temperatures such that the grain growth of the AlCu will be inhibited and the switching element can be fabricated with a consistent structure, which leads to a consistent, predictable capacitance during operation.

“In one embodiment, a MEMS DVC comprises at least one electrode; and a switching element movable from a first position spaced a first distance from the at least one electrode and a second position spaced a second distance from the at least one electrode, the at least one electrode comprising a multilayer stack of materials comprising at least one layer of AlCu having at least one layer containing titanium disposed thereon.

“In another embodiment, a MEMS DVC comprises a substrate having a first electrode, a second electrode and an RF electrode disposed therein; a first dielectric layer disposed over the second electrode and the RF electrode; and a switching element coupled to the first electrode and movable from a first position spaced from the first dielectric layer and a second position in contact with the first dielectric layer. The RF electrode comprises a multilayer stack comprising an AlCu layer and a titanium containing layer disposed thereon.

“In another embodiment, a method of manufacturing a MEMS DVC comprises forming an electrode comprising a multilayer stack of AlCu with a titanium containing layer thereon; and diffusing the titanium into the AlCu.”

The claims supplied by the inventors are:

“The invention claimed is:

“1. A MEMS DVC, comprising: at least one electrode; and a switching element movable from a first position spaced a first distance from the at least one electrode and a second position spaced a second distance from the at least one electrode, the at least one electrode comprising a multilayer stack of materials comprising a first layer containing titanium, the first layer containing titanium comprising a first multilayer structure comprising titanium and titanium nitride disposed on the titanium, a first layer of AlCu, a second layer containing titanium, the second layer containing titanium comprising a second multilayer structure comprising titanium and titanium nitride disposed on the titanium, a second layer of AlCu, and a third layer containing titanium, wherein at least one of the first layer containing titanium or the second layer containing titanium is disposed between the first layer of AlCu and the second layer of AlCu, and wherein the third layer containing titanium comprises a layer of titanium having a first thickness and a layer of titanium nitride disposed on the layer of titanium, wherein the layer of titanium nitride has a second thickness different than the first thickness.

“2. The MEMS DVC of claim 1, further comprising: a third layer of AlCu; and a fourth layer containing titanium.

“3. The MEMS DVC of claim 2, wherein the fourth layer containing titanium comprises titanium nitride.

“4. The MEMS DVC of claim 1, wherein the first layer of AICu has titanium diffused at least partially therein from an adjacent layer containing titanium.

“5. The MEMS DVC of claim 1, wherein the titanium of the first layer comprising the first multilayer structure has a thickness between about 20 nm and 50 nm.

“6. The MEMS DVC of claim 1, wherein the titanium of the first layer comprising the first multilayer structure has a thickness between about 20 nm and 50 nm.

“7. The MEMS DVC of claim 1, further comprising: a third layer of AICu; and a fourth layer containing titanium, the fourth layer containing titanium comprising a fourth multilayer structure containing titanium and titanium nitride disposed on the titanium.

“8. The MEMS DVC of claim 7, wherein the titanium of the fourth layer containing titanium has thickness between about 20 nm and 50 nm.

“9. A MEMS DVC, comprising: a substrate having a first electrode, a second electrode and an RF electrode disposed therein, wherein one or more of the first electrode, second electrode and RF electrode comprises a multilayer stack of materials comprising a first layer containing titanium, the first layer containing titanium comprising a first multilayer structure comprising titanium and titanium nitride disposed on the titanium, a first layer of AlCu, a second layer containing titanium, the second layer containing titanium comprising a second multilayer structure comprising titanium and titanium nitride disposed on the titanium, a second layer of AlCu , and a third layer containing titanium, wherein the second layer containing titanium is disposed between the first AlCu layer and the second AlCu layer, and wherein the third layer containing titanium comprises a layer of titanium having a first thickness and a layer of titanium nitride disposed on the layer of titanium, wherein the layer of titanium nitride has a second thickness different than the first thickness; a first dielectric layer disposed over the second electrode and the RF electrode; and a switching element coupled to the first electrode and movable from a first position spaced from the first dielectric layer and a second position in contact with the first dielectric layer.

“10. The MEMS DVC of claim 9, further comprising: a third layer of AlCu; and a fourth layer containing titanium.

“11. The MEMS DVC of claim 10, wherein the fourth layer containing titanium comprises titanium nitride.

“12. The MEMS DVC of claim 9, wherein the first layer of AlCu has titanium diffused at least partially therein from an adjacent layer containing titanium.

“13. The MEMS DVC of claim 9, wherein the titanium of the first layer containing titanium has a thickness between about 20 nm and 50 nm.

“14. The MEMS DVC of claim 9, wherein the titanium of the first layer containing titanium has a thickness between about 20 nm and 50 nm.

“15. The MEMS DVC of claim 9, further comprising: a third layer of AICu; and a fourth layer containing titanium, the fourth layer containing titanium comprising a fourth multilayer structure comprising titanium and titanium nitride disposed on the titanium.

“16. The MEMS DVC of claim 15, wherein the titanium of the fourth layer containing titanium has a thickness between about 20 nm and 50 nm.”

For more information, see this patent: Renault, Mickael. RF MEMS Electrodes With Limited Grain Growth. U.S. Patent Number 10,301,173, filed , and published online on . Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=10,301,173.PN.&OS=PN/10,301,173RS=PN/10,301,173

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