Acoustic decoupling in cMUTs
First Claim
Patent Images
1. A capacitive micromachined ultrasonic transducer (cMUT), comprising:
- a base having a lower base portion and an upper base portion, the lower base portion and the upper base portion defining a cavity therebetween, the upper base portion having a first electrode; and
a movable layer disposed above the upper base portion and supported by a support connected to the upper base portion, the support spacing the movable layer from the upper base portion to define a transducing space, the movable layer having a second electrode opposing the first electrode to evacuate a variable capacitor between the base and the movable layer.
4 Assignments
0 Petitions
Accused Products
Abstract
A capacitive micromachined ultrasonic transducer (cMUT) has an acoustic decoupling feature. A cavity is introduced underneath the regular cMUT element, preferably in the substrate, to provide acoustic decoupling. Trenches are also introduced to separate the cMUT elements and to provide further acoustic decoupling. The acoustic decoupling feature may be used in both conventional membrane-based cMUT and the newer embedded-spring cMUT (ESCMUT). Exemplary fabrication methods are also described.
78 Citations
22 Claims
-
1. A capacitive micromachined ultrasonic transducer (cMUT), comprising:
-
a base having a lower base portion and an upper base portion, the lower base portion and the upper base portion defining a cavity therebetween, the upper base portion having a first electrode; and a movable layer disposed above the upper base portion and supported by a support connected to the upper base portion, the support spacing the movable layer from the upper base portion to define a transducing space, the movable layer having a second electrode opposing the first electrode to evacuate a variable capacitor between the base and the movable layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A capacitive micromachined ultrasonic transducer (cMUT), comprising:
-
a base having a lower base portion and an upper base portion, the lower base portion and the upper base portion defining a cavity therebetween; a spring layer disposed above the upper base portion and anchored by a spring anchor connected to the upper base portion, the spring anchor spacing the spring layer from the upper base portion to form a cantilever-like structure having an anchored portion and a movable portion; and a surface plate disposed above the spring layer and supported by a spring-plate connector connected to the movable portion of the spring layer, the spring-plate connector spacing the surface plate from the spring layer to define a transducing space, wherein the surface plate includes a top electrode, and wherein at least one of the spring layer, the spring anchor and the upper base portion includes a bottom electrode opposing the top electrode to evacuate a variable capacitor therebetween. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
-
-
20. A method for fabricating a capacitive micromachined ultrasonic transducer, the method comprising:
-
providing a substrate; forming a cavity on a surface of the substrate; placing a cover layer over the cavity; and completing a cMUT structure on top of the cover layer, wherein the cMUT structure includes a spring layer disposed above the cover layer and a first electrode and a second electrode defining a variable capacitor, at least one of the first electrode and the second electrode being movable to vary the variable capacitor. - View Dependent Claims (21)
-
-
22. A method for fabricating a capacitive micromachined ultrasonic transducer, the method comprising:
-
providing a substrate; forming a cavity on a surface of the substrate; placing a cover layer over the cavity; forming a spring anchor on the cover layer; placing a spring layer over the spring anchor, when placed the spring layer having an anchored portion and a movable portion, the anchored portion being anchored and the spring anchor; forming a spring-plate connector on the movable portion of the spring layer; and placing a surface plate over the spin-plate connector, wherein the cMUT structure includes a first electrode and a second electrode defining a variable capacitor, at least one of the first electrode and the second electrode being movable to vary the variable capacitor.
-
Specification