Low-temperature micromachined cMUTs with fully-integrated analogue front-end electronics

Noble, R.A.; Davies, R.; King, D.O.; Day, Mike; Jones, Alan R.; McIntosh, J.S.; Hutchins, D.A.; Saul, P.H.

doi:10.1109/ultsym.2002.1192474

Cited by 31 publications

(17 citation statements)

References 4 publications

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“…To integrate 2-D transducer arrays with associated transmit/receive electronics, as briefly discussed in Section I, several different interconnection schemes have been proposed in the literature. Monolithic integration of CMUTs with electronic circuits has also been proposed [35]- [38]. Monolithic integration of microelectromechanical systems (MEMS) with electronic circuits usually results in a compromise of the performance of one or both components.…”

Section: -D Cmut Arraysmentioning

confidence: 99%

“…In this approach, the number of available design parameters is also reduced due to the use of a standard process. An alternate method uses postprocessing to fabricate CMUT elements over the electronics chip, which is built using a standard CMOS process [37], [38]. The wafer with the electronics goes through passivation and CMP processes before the CMUT fabrication process.…”

Section: -D Cmut Arraysmentioning

confidence: 99%

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Volumetric ultrasound imaging using 2-D CMUT arrays

Oralkan

Ergun

Cheng

et al. 2003

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

167

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Recently, capacitive micromachined ultrasonic transducers (CMUTs) have emerged as a candidate to overcome the difficulties in the realization of 2-D arrays for real-time 3-D imaging. In this paper, we present the first volumetric images obtained using a 2-D CMUT array. We have fabricated a 128 128-element 2-D CMUT array with through-wafer via interconnects and a 420-m element pitch. As an experimental prototype, a 32 64-element portion of the 128 128-element array was diced and flipchip bonded onto a glass fanout chip. This chip provides individual leads from a central 16 16-element portion of the array to surrounding bondpads. An 8 16-element portion of the array was used in the experiments along with a 128-channel data acquisition system. For imaging phantoms, we used a 2.37-mm diameter steel sphere located 10 mm from the array center and two 12-mm-thick Plexiglas plates located 20 mm and 60 mm from the array. A 4 4 group of elements in the middle of the 8 16-element array was used in transmit, and the remaining elements were used to receive the echo signals. The echo signal obtained from the spherical target presented a frequency spectrum centered at 4.37 MHz with a 100% fractional bandwidth, whereas the frequency spectrum for the echo signal from the parallel plate phantom was centered at 3.44 MHz with a 91% fractional bandwidth. The images were reconstructed by using RF beamforming and synthetic phased array approaches and visualized by surface rendering and multiplanar slicing techniques. The image of the spherical target has been used to approximate the point spread function of the system and is compared with theoretical expectations. This study experimentally demonstrates that 2-D CMUT arrays can be fabricated with high yield using silicon ICfabrication processes, individual electrical connections can be provided using through-wafer vias, and flip-chip bonding can be used to integrate these dense 2-D arrays with electronic circuits for practical 3-D imaging applications. Manuscript

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Section: -D Cmut Arraysmentioning

confidence: 99%

Section: -D Cmut Arraysmentioning

confidence: 99%

Volumetric ultrasound imaging using 2-D CMUT arrays

Oralkan

Ergun

Cheng

et al. 2003

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

167

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“…Compared to general purpose ultrasound imaging systems, IVUS imaging system requirements are quite challenging and in particular the probe in IVUS imaging systems is based on a catheter with a diameter of the order of 1 mm or less. The combination of high frequency, small form factor, and good performance requires ultrasound transducers and interface electronics to be tightly integrated [2,3]. In such catheter based IVUS imaging systems, the latest ultrasound sensors, capacitive micro-machined ultrasound transducers (CMUTs), fit best compared to conventional piezoelectric transducers, as CMUTs are compatible with the well known CMOS process.…”

Section: Introductionmentioning

confidence: 99%

“…These CMUTs are replacing the long-established piezoelectric transducers in high frequency and high resolution ultrasound imaging due to their attractive features of micro-fabrication, wide bandwidth, very high level of integration, and batch fabrication [4][5][6]. CMUTs can easily be integrated with CMOS front-end electronics either through flip-chip bonding [7][8][9] or monolithically through CMUTs on the CMOS process [2,3,10,11]. The integration of CMOS electronic circuits with CMUTs will greatly cut down the cost of ultrasound imaging systems as the mass production of CMOS electronic integrated circuits is very cheap.…”

Section: Introductionmentioning

confidence: 99%

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Inverter-based 1 V analog front-end amplifiers in 90 nm CMOS for medical ultrasound imaging

Reddy

Singh

Ytterdal

2010

Analog Integr Circ Sig Process

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In this paper, we present the design and experimental evaluation of 1 V analog front-end amplifiers designed in 90 nm CMOS technology for capacitive micromachined ultrasound transducers (CMUTs) for medical ultrasound imaging systems. We propose two front-end amplifier topologies based on an inverter-based cascode amplifier; the first is a continuous time amplifier and the second is a charge sampling amplifier (CSA). The proposed front-end amplifiers are designed to amplify the signals from CMUTs in the frequency bandwidth from 15 to 45 MHz with a centre frequency of 30 MHz. From the measurements, the continuous time single-ended transimpedance amplifier achieves a voltage gain of 19 dB, an output noise power spectral density of 0.042 (lV)/ SQRT(Hz) at a centre-frequency of 30 MHz, and a total harmonic distortion of -23 dB at 450 mV p-p output voltage at 30 MHz input signal frequency. It draws only 598 lA per amplifier from a 1 V power supply. Its area measured only about 32 lm 9 32 lm per amplifier. On the other hand, a sampling based front-end amplifier [CSA] achieves a transfer gain of 17.4 dB at an input signal frequency of 30 MHz and an upper 3 dB cut-off frequency of 46 MHz at a sampling clock frequency of 100 MHz. It consumes 586 lA per amplifier from a 1 V power supply and achieves a signal-to-noise (SNR) ratio of 45.7 dB with a peak-to-peak output signal amplitude of 500 mV at a sampling frequency of 100 MHz. It occupies an area of 1470.2 lm 2 (which is equivalent to 38 lm 9 38 lm), which also includes the area of the switches for the CSA that will be used for the single CMUT element.

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