Abstract: A capacitive micromachined ultrasonic transducers (cMUT) system has two cMUTs connected to each other. The first cMUT is adapted for operation in a transmission mode, and the second cMUT is adapted for operation in the reception mode. The first cMUT and the second cMUT share a common signal line and are connected in a manner to allow the first cMUT and the second cMUT to have bias voltages that can be independently set. In one embodiment, one of the cMUTs is connected to a voltage controller to regulator the voltage applied there on. Various connection configurations, including connections in series and connections in parallel, are disclosed. The cMUT system configurations allow separate optimization for transmission and reception and better flexibility in operation.

Abstract: A MEMS ultrasonic device has an array of PZT transducer elements and a cMUT structure bonded to the array of PZT transducer elements. The MEMS ultrasonic device can be adapted for ultrasonic imaging. The cMUT structure may serve as an active MEMS acoustic filter having at least two acoustic I/O ports to alter an input acoustic signal to an output acoustic signal. The first I/O port is adapted for interfacing with a medium, and the second I/O port for passing an acoustic signal to an acoustic transducer. An array of MEMS acoustic filters may be designed to function as an acoustic lens. Fabrication methods to make the same are also disclosed.

Abstract: A capacitive micromachined ultrasonic transducers (cMUT) uses signal control methods to reduce harmonic distortion of the output signal. The method uses an AC transmission input signal characterized with a frequency ? and takes the second-order frequency component with frequency 2?, rather than the first-order frequency component with the base frequency ?, as the desired output pressure signal. A frequency ? is preferably equal to ?0/2, where ? is the desired cMUT output frequency. Various examples of AC transmission input signals, in combination with or without a DC bias signal, that are suitable for producing a large second-order frequency component and small (ideally zero) first-order frequency component are disclosed.

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.

Abstract: A micro-electro-mechanical transducer (such as a cMUT) is disclosed. The transducer has a base, a spring layer placed over the base, and a mass layer connected to the spring layer through a spring-mass connector. The base includes a first electrode. The spring layer or the mass layer includes a second electrode. The base and the spring layer form a gap therebetween and are connected through a spring anchor. The mass layer provides a substantially independent spring mass contribution to the spring model without affecting the equivalent spring constant. The mass layer also functions as a surface plate interfacing with the medium to improve transducing performance. Fabrication methods to make the same are also disclosed.

Abstract: Structure for capacitive micromachined ultrasonic transducer (CMUT) device or other vibrating membrane device having non-uniform membrane so that membrane mass and stiffness characteristics may be substantially independently adjusted. CMUT having trenched membrane and/or membrane with non-uniform thickness or density. Method for operating transducer or vibrating membrane device. Array of devices at least some of which have non-uniform membrane properties. CMUT comprising substrate, support for membrane, and membrane extending over support to create cavity, membrane having non-uniform membrane thickness resulting from at least one of: thickening on upper surface of the membrane outside of cavity, thickening on lower surface of membrane inside cavity, trench on upper surface of membrane, trench on lower surface of the membrane, and any combination of two or more of these. Method for fabricating CMUT or vibrating membrane device having non-uniform membrane.

Abstract: A MEMS acoustic filter has a MEMS resonator and at least two acoustic I/O ports to alter an input acoustic signal to an output acoustic signal. The first I/O port is adapted for interfacing with a medium, and the second I/O port for passing an acoustic signal to an acoustic transducer. Multiple MEMS resonators may be stacked to form a high order acoustic filter. An array of MEMS acoustic filters may be designed to function as an acoustic lens. The MEMS acoustic filter is particularly useful with an ultrasonic transducer, such as PZT and MUT. Fabrication methods to make the same are also disclosed.

Abstract: A micro-electro-mechanical transducer (such as a cMUT) is disclosed. The transducer has a base having a lower portion and an upper portion; a top plate disposed above the upper portion of the base forming a gap therebetween; and a spring-like structure disposed between the top plate and the lower portion of the base. The spring-like structure has a spring layer connected to the lower portion of the base and a spring-plate connector connecting the spring layer and a top plate. In an alternate embodiment, the spring-like has a vertical bendable connector connecting the top plate and the lower portion of the base. The spring-like structure transports the top plate vertically in a piston like manner to perform the function of the transducer. Fabrication methods to make the same are also disclosed.

Abstract: A micro-electro-mechanical transducer (such as a cMUT) is disclosed. The transducer has a base having a lower portion and an upper portion; a top plate disposed above the upper portion of the base forming a gap therebetween; and a spring-like structure disposed between the top plate and the lower portion of the base. The spring-like structure has a spring layer connected to the lower portion of the base and a spring-plate connector connecting the spring layer and a top plate. In an alternate embodiment, the spring-like has a vertical bendable connector connecting the top plate and the lower portion of the base. The spring-like structure transports the top plate vertically in a piston like manner to perform the function of the transducer. Fabrication methods to make the same are also disclosed.

Abstract: An electrostatic actuator/transducer has a comb driver and can be adapted for a variety of applications, particularly as a capacitive micromachined ultrasonic transducer. The comb driver has two electrodes each connected to a set of comb fingers. The two sets of comb fingers interdigitate with each other, and in one embodiment each has a saw-toothed shape. One electrode is connected to a spring structure and movable along a vertical direction to engage and disengage the two sets of comb fingers. The movable portion is adapted to perform an actuation function and/or a sense of function. Fabrication methods for making the electrostatic actuator/transducer are also disclosed.

Abstract: The embodiments of the present invention provide a CMUT array and method of fabricating the same. The CMUT array has CMUT elements individually or respectively addressable from a backside of a substrate on which the CMUT array is fabricated. In one embodiment, a CMUT array is formed on a front side of a very high conductivity silicon substrate. Through wafer trenches are etched into the substrate from the backside of the substrate to electrically isolate individual CMUT elements formed on the front side of the substrate. Electrodes are formed on the backside of the substrate to individually address the CMUT elements through the substrate.

Abstract: A capacitive micromachined ultrasonic transducer (CMUT) includes a structured membrane which possesses improved frequency response characteristics. Some embodiments provide CMUTs which include a substrate, a first electrode, a second movable electrode, and a structured membrane. The movable second electrode is spaced apart from the first electrode and is coupled to the structured membrane. The structured membrane is shaped to possess a selected resonant frequency or an optimized frequency response. The structured membrane can include a plate and a beam coupled to the plate such that the resonant frequency of the structured membrane is greater than the resonant frequency of the plate. Furthermore, the ratio of the resonant frequency of the structured membrane over the mass of the structured membrane can be greater than the ratio of the resonant frequency of the plate over the mass of the plate. In some embodiments, the CMUT is an embedded spring ESCMUT.

Abstract: Implementations of a cMUT have a telemetric antenna operative to telemetrically transmit an output signal generated by the cMUT in reception mode (RX). The cMUT generates the output signal by converting a received energy applied on the cMUT. The received energy may be an acoustic wave or a low-frequency pressure signal. The acoustic wave may be generated by a separate acoustic energy source. The cMUT may form a modulated signal using a carrier signal modulated with the output signal, and telemetrically transmit the modulated signal carrying the output signal to increase efficiency. The antenna may also receive an input signal from outside to telemetrically power on the cMUT.

Abstract: A micro-electro-mechanical transducer (such as a cMUT) is disclosed. The transducer has a substrate, a top plate, and a resilient structure therebetween. The resilient structure has multiple connectors distributed over the device element area to vertically transport the top player with distributed support. The resilient structure may be cantilevers formed using a middle spring layer covering cavities on the substrate. Connectors define a transducing space below the top plate. The resilient structure enables a vertical displacement of the connectors, which transports the top plate in a piston-like motion to change the transducing space and to effectuate energy transformation. No separate cells are necessary for each addressable transducer element. Multiple device elements can be made on the same substrate.

Abstract: A capacitive ultrasonic transducer is described which include one or more cells including a cavity defined by a membrane electrode supported spaced from a support electrode by insulating walls with a patterned isolation layer having isolation posts or areas located in said cavity to prevent the electrodes for coming into contact during operation of the transducer, and to minimize the accumulation of charge as compared to a non-patterned isolation layer for preventing contact of the electrodes during operation of the transducer.

Abstract: A capacitive micromachined ultrasonic transducer (cMUT) system uses a modulation technique to increase cMUT sensitivity. An AC carrier signal is applied to the cMUT through a modulation signal port to modulate the signal. The higher frequency of the AC carrier signal carries the real signal to a high frequency range to increase the output current signal level. The real signal is later recovered by demodulation. The technique is applicable in both the reception mode and the transmission mode.

Abstract: A micro-electro-mechanical transducer (such as a cMUT) having two electrodes separated by an insulator with an insulation extension is disclosed. The two electrodes define a transducing gap therebetween. The insulator has an insulating support disposed generally between the two electrodes and an insulation extension extending into at least one of two electrodes to increase the effective insulation without having to increase the transducing gap. Methods for fabricating the micro-electro-mechanical transducer are also disclosed. The methods may be used in both conventional membrane-based cMUTs and cMUTs having embedded springs transporting a rigid top plate.

Abstract: A through-wafer interconnect and a method for fabricating the same are disclosed. The method starts with a conductive wafer to form a patterned trench by removing material of the conductive wafer. The patterned trench extends in depth from the front side to the backside of the wafer, and has an annular opening generally dividing the conductive wafer into an inner portion and an outer portion whereby the inner portion of the conductive wafer is insulated from the outer portion and serves as a through-wafer conductor. A dielectric material is formed or added into the patterned trench mechanical to support and electrically insulate the through-wafer conductor. Multiple conductors can be formed in an array.

Abstract: A micro-electro-mechanical transducer (such as a cMUT) is disclosed. The transducer has a substrate, a top plate, and a middle spring layer therebetween. The substrate and the middle spring layer define cavities therebetween sidewalled by standing features. The middle spring layer is anchored by the standing features to create cantilevers over the cavities to enable a vertical displacement of connectors placed on the middle spring layer. The connectors define a transducing space between the middle spring layer and the top plate. The top plate is transported by the vertical displacement of the connectors in a piston-like motion to change the transducing space and to effectuate energy transformation. Various configurations of cantilevers, including single cantilevers, back-to-back double cantilevers and head-to-head double cantilevers (bridges) are possible.

Abstract: A method for fabricating a micro-electro-mechanical device (such as a cMUT) is disclosed. The method combines a substrate, a middle spring layer and a top plate using wafer bonding technology or sacrificial technology. A cavity is formed on either the top of the substrate or the bottom of the middle spring layer. A connector is formed on either the top of the middle spring layer or the bottom of the top plate. Upon joining the three layers, the connector defines a transducing space between the top plate and the middle spring layer. The connector is horizontally distanced from the sidewall to define a cantilever anchored at the sidewall. The cantilever and the cavity allow a vertical displacement of the connector, which transports the top wafer in a piston-like motion to change the transducing space. Multiple device elements can be made on the same substrate.