CMUT-in-CMOS ultrasonic transducer arrays with on-chip electronics

Cheng, Xinjian; Lemmerhirt, D.F.; Kripfgans, Oliver D.; Zhang, M.; Yang, Chen; Rich, Collin A.; Fowlkes, J. Brian

doi:10.1109/sensor.2009.5285878

Cited by 17 publications

(8 citation statements)

References 5 publications

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“…This post-processing is kept minimal in a process called ‘CMUT-in-CMOS’ by augmenting a standard foundry process only with two blanket post-process steps for sacrificial etching and cavity sealing [Cheng09]. Although this process is fairly simple, it still suffers from the limitations on the device dimensions in the vertical direction because layers available in the standard foundry process are utilized as sacrificial layer.…”

Section: Integration With Electronic Circuitsmentioning

confidence: 99%

Capacitive micromachined ultrasonic transducers for medical imaging and therapy

Khuri‐Yakub

Oralkan

2011

J. Micromech. Microeng.

267

129

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Capacitive micromachined ultrasonic transducers (CMUTs) have been subject to extensive research for the last two decades. Although they were initially developed for air-coupled applications, today their main application space is medical imaging and therapy. This paper first presents a brief description of CMUTs, their basic structure, and operating principles. Our progression of developing several generations of fabrication processes is discussed with an emphasis on the advantages and disadvantages of each process. Monolithic and hybrid approaches for integrating CMUTs with supporting integrated circuits are surveyed. Several prototype transducer arrays with integrated frontend electronic circuits we developed and their use for 2-D and 3-D, anatomical and functional imaging, and ablative therapies are described. The presented results prove the CMUT as a MEMS technology for many medical diagnostic and therapeutic applications.

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Section: Integration With Electronic Circuitsmentioning

confidence: 99%

Capacitive micromachined ultrasonic transducers for medical imaging and therapy

Khuri‐Yakub

Oralkan

2011

J. Micromech. Microeng.

267

129

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“…Remaining structure is then e, silicon oxide and polysilicon layers [2]. In other approach, keeping metal layers for a device design, a sacrificial silicon oxide can be removed with saturated with aluminum (SiloxVapox) MEMS fabrication cost maskless etching and a potential to integrate a MEMS device with electronics on the Acoustic devices as microphones [3][4][5] or CMUTs machined ultrasonic transducers) [6,7], have CMOS approaches that require like material deposition to build the entire ost of microphone designs consist of a agm and a perforated backplate backplate, there is chamber that makes the air evacuation from the air gap chamber is usually obtained by back side have studied and developed a model of a condenser microphone with a different approach that does not require backside bulk micromachining. Our microphone structure is similar to conventional MEMS microphone but the movable diaphragm is perforated with small holes to allow SiO 2 etching as well as microphone ventilation.…”

Section: Mems Technology Acoustic Mems Front-mentioning

confidence: 99%

“…Acoustic devices as microphones [3 (capacitive micro-machined ultrasonic transducers) [6,7], have been fabricated using post-CMOS approaches some supplementary technology steps, like material deposition [3,6,7] or backside substrate etch [4,5], to build the entire MEMS structure. Most of microphone design sealed movable diaphragm and a perforated backplate separated by an air gap (Fig.…”

Section: Introductionmentioning

confidence: 99%

CMOS-MEMS technology with front-end surface etching of sacrificial SiO<inf>2</inf> dedicated for acoustic devices

Esteves¹,

Rufer²,

Basrour³

et al. 2013

5th IEEE International Workshop on Advances in Sensors and Interfaces IWASI

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“…Processing of the CMUTs can be simultaneously accomplished with the fabrication of electronics utilizing reliable and well-established CMOS processing techniques [11]. Due to the parallel processing, the overall fabrication time and processing costs are reduced.…”

Section: Cmut-cmos Integration Techniquesmentioning

confidence: 99%

Monolithic CMUT-on-CMOS Integration for Intravascular Ultrasound Applications

Zahorian

Hochman

et al. 2011

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

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One of the most important promises of capacitive micromachined ultrasonic transducer (CMUT) technology is integration with electronics. This approach is required to minimize the parasitic capacitances in the receive mode, especially in catheter based volumetric imaging arrays where the elements need to be small. Furthermore, optimization of the available silicon area and minimized number of connections occurs when the CMUTs are fabricated directly above the associated electronics. Here, we describe successful fabrication and performance evaluation of CMUT arrays for intravascular imaging on custom designed CMOS receiver electronics from a commercial IC foundry. The CMUT on CMOS process starts with surface isolation and mechanical planarization of the CMOS electronics to reduce topography. The rest of the CMUT fabrication is achieved by modifying a low temperature micromachining process through the addition of a single mask and developing a dry etching step to produce sloped sidewalls for simple and reliable CMUT to CMOS interconnection. This CMUT to CMOS interconnect method reduced the parasitic capacitance by a factor of 200 when compared with a standard wire bonding method. Characterization experiments indicate that the CMUT on CMOS elements are uniform in frequency response and are similar to CMUTs simultaneously fabricated on standard silicon wafers without electronics integration. Experiments on a 1.6 mm diameter dual-ring CMUT array with a 15 MHz center frequency show that both the CMUTs and the integrated CMOS electronics are fully functional. The SNR measurements indicate that the performance is adequate for imaging CTOs located 1 cm away from the CMUT array.

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CMUT-in-CMOS ultrasonic transducer arrays with on-chip electronics

Cited by 17 publications

References 5 publications

Capacitive micromachined ultrasonic transducers for medical imaging and therapy

Capacitive micromachined ultrasonic transducers for medical imaging and therapy

CMOS-MEMS technology with front-end surface etching of sacrificial SiO<inf>2</inf> dedicated for acoustic devices

Monolithic CMUT-on-CMOS Integration for Intravascular Ultrasound Applications

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