Download or read book Capacitive Micromachined Ultrasonic Transducers with Through wafer Interconnects written by Xuefeng Zhuang and published by . This book was released on 2008 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interface Engineering of Capacitive Micromachined Ultrasonic Transducers for Medical Applications written by Der-Song Lin and published by Stanford University. This book was released on 2011 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: Capacitive micromachined ultrasonic transducers (CMUTs), have been widely studied in academia and industry over the last decade. CMUTs provide many benefits over traditional piezoelectric transducers including improvement in performance through wide bandwidth, and ease of electronics integration, with the potential to batch fabricate very large 2D arrays with low-cost and high-yield. Though many aspects of CMUT technology have been studied over the years, packaging the CMUT into a fully practical system has not been thoroughly explored. Two important interfaces of packaging that this thesis explores are device encapsulation (the interface between CMUTs and patients) and full electronic integration of large scale 2D arrays (the interface between CMUTs and electronics). In the first part of the work, I investigate the requirements for the CMUT encapsulation. For medical usage, encapsulation is needed to electrically insulate the device, mechanically protect the device, and maintain transducer performance, especially the access of the ultrasound energy. While hermetic sealing can protect many other MEMS devices, CMUTs require mechanical interaction to a fluid, which makes fulfilling the previous criterion very challenging. The proposed solution is to use a viscoelastic material with the glass-transition-temperature lower than room temperature, such as Polydimethylsiloxane (PDMS), to preserve the CMUT static and dynamic performance. Experimental implementation of the encapsulated imaging CMUT arrays shows the device performance was maintained; 95 % of efficiency, 85% of the maximum output pressure, and 91% of the fractional bandwidth (FBW) can be preserved. A viscoelastic finite element model was also developed and shows the performance effects of the coating can be accurately predicted. Four designs, providing acoustic crosstalk suppression, flexible substrate, lens focusing, and blood flow monitoring using PDMS layer were also demonstrated. The second part of the work, presents contributions towards the electronic integration and packaging of large-area 2-D arrays. A very large 2D array is appealing for it can enable advanced novel imaging applications, such as a reconfigurable array, and a compression plate for breast cancer screening. With these goals in mind, I developed the first large-scale fully populated and integrated 2D CMUTs array with 32 by 192 elements. In this study, I demonstrate a flexible and reliable integration approach by successfully combining a simple UBM preparation technique and a CMUTs-interposer-ASICs sandwich design. The results show high shear strength of the UBM (26.5 g), 100% yield of the interconnections, and excellent CMUT resonance uniformity ([lowercase Sigma] = 0.02 MHz). As demonstrated, this allows for a large-scale assembly of a tile-able array by using an interposer. Interface engineering is crucial towards the development of CMUTs into a practical ultrasound system. With the advances in encapsulation technique with a viscoelastic polymer and the combination of the UBM technique to the TSV fabrication for electronics integration, a fully integrated CMUT system can be realized.
Download or read book Ultra Wideband CapacitiveMicromachined Ultrasonic Transducers CMUTs and Through Wafer Interconnects for Applications in Immersion and Air written by Oluwafemi Joel Adelegan and published by . This book was released on 2021 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nanostructure Based Sensors for Gas Sensing from Devices to Systems written by Sabrina Grassini and published by MDPI. This book was released on 2019-10-29 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of solid state gas sensors based on microtransducers and nanostructured sensing materials is the key point in the design of portable measurement systems able to reach sensing and identification performance comparable with analytical ones. In such a context several efforts must be spent of course in the development of the sensing material, but also in the choice of the transducer mechanism and its structure, in the electrical characterization of the performance and in the design of suitable measurement setups. This call for papers invites researchers worldwide to report about their novel results on the most recent advances and overview in design and measurements for applications in gas sensors, along with their relevant features and technological aspects. Original research papers are welcome (but not limited) on all aspects that focus on the most recent advances in: (i) basic principles and modeling of gas and VOCs sensors; (ii) new gas sensor principles and technologies; (iii) Characterization and measurements methodologies; (iv) transduction and sampling systems; (vi) package optimization; (vi) gas sensor based systems and applications.
Download or read book Capacitive Micromachined Ultrasonic Transducers CMUTs Built with Wafer bonding Technology written by Yongli Huang and published by . This book was released on 2005 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 3D and Circuit Integration of MEMS written by Masayoshi Esashi and published by John Wiley & Sons. This book was released on 2021-03-16 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explore heterogeneous circuit integration and the packaging needed for practical applications of microsystems MEMS and system integration are important building blocks for the “More-Than-Moore” paradigm described in the International Technology Roadmap for Semiconductors. And, in 3D and Circuit Integration of MEMS, distinguished editor Dr. Masayoshi Esashi delivers a comprehensive and systematic exploration of the technologies for microsystem packaging and heterogeneous integration. The book focuses on the silicon MEMS that have been used extensively and the technologies surrounding system integration. You’ll learn about topics as varied as bulk micromachining, surface micromachining, CMOS-MEMS, wafer interconnection, wafer bonding, and sealing. Highly relevant for researchers involved in microsystem technologies, the book is also ideal for anyone working in the microsystems industry. It demonstrates the key technologies that will assist researchers and professionals deal with current and future application bottlenecks. Readers will also benefit from the inclusion of: A thorough introduction to enhanced bulk micromachining on MIS process, including pressure sensor fabrication and the extension of MIS process for various advanced MEMS devices An exploration of epitaxial poly Si surface micromachining, including process condition of epi-poly Si, and MEMS devices using epi-poly Si Practical discussions of Poly SiGe surface micromachining, including SiGe deposition and LP CVD polycrystalline SiGe A concise treatment of heterogeneously integrated aluminum nitride MEMS resonators and filters Perfect for materials scientists, electronics engineers, and electrical and mechanical engineers, 3D and Circuit Integration of MEMS will also earn a place in the libraries of semiconductor physicists seeking a one-stop reference for circuit integration and the practical application of microsystems.
Download or read book MEMS Technology for Biomedical Imaging Applications written by Qifa Zhou and published by MDPI. This book was released on 2019-10-23 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biomedical imaging is the key technique and process to create informative images of the human body or other organic structures for clinical purposes or medical science. Micro-electro-mechanical systems (MEMS) technology has demonstrated enormous potential in biomedical imaging applications due to its outstanding advantages of, for instance, miniaturization, high speed, higher resolution, and convenience of batch fabrication. There are many advancements and breakthroughs developing in the academic community, and there are a few challenges raised accordingly upon the designs, structures, fabrication, integration, and applications of MEMS for all kinds of biomedical imaging. This Special Issue aims to collate and showcase research papers, short commutations, perspectives, and insightful review articles from esteemed colleagues that demonstrate: (1) original works on the topic of MEMS components or devices based on various kinds of mechanisms for biomedical imaging; and (2) new developments and potentials of applying MEMS technology of any kind in biomedical imaging. The objective of this special session is to provide insightful information regarding the technological advancements for the researchers in the community.
Download or read book Computational Science and Engineering written by Arpan Deyasi and published by CRC Press. This book was released on 2016-12-19 with total page 355 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational Science and Engineering contains peer-reviewed research presented at the International Conference on Computational Science and Engineering (RCC Institute of Information Technology, Kolkata, India, 4-6 October 2016). The contributions cover a wide range of topics: - electronic devices - photonics - electromagnetics - soft computing - artificial intelligence - modern communication systems Focussing on strong theoretical and methodological approaches and applications, Computational Science and Engineering will be of interest to academia and professionals involved or interested in the above mentioned domains.
Download or read book Mems Nems written by Cornelius T. Leondes and published by Springer Science & Business Media. This book was released on 2007-10-08 with total page 2142 pages. Available in PDF, EPUB and Kindle. Book excerpt: This significant and uniquely comprehensive five-volume reference is a valuable source for research workers, practitioners, computer scientists, students, and technologists. It covers all of the major topics within the subject and offers a comprehensive treatment of MEMS design, fabrication techniques, and manufacturing methods. It also includes current medical applications of MEMS technology and provides applications of MEMS to opto-electronic devices. It is clearly written, self-contained, and accessible, with helpful standard features including an introduction, summary, extensive figures and design examples with comprehensive reference lists.
Download or read book Acoustical Imaging written by Walter Arnold and published by Springer Science & Business Media. This book was released on 2004-09-16 with total page 802 pages. Available in PDF, EPUB and Kindle. Book excerpt: Acoustical imaging has become an indispensable tool in a variety of fields. Since its introduction, the applications have grown and cover a variety of techniques, producing significant results in fields as disparate as medicine and seismology. Cutting-edge trends continue to be discussed worldwide. This book contains the proceedings of the 27th International Symposium on Acoustical Imaging (AI27), which took place in Saarbrücken, Germany, from March 24th to March 27th 2003. The Symposium belongs to a conference series in existence since 1968. AI27 comprised sessions on: Medical Imaging, Non-Destructive Testing, Seismic Imaging, Physics and Mathematics of Acoustical Imaging, Acoustic Microscopy. During two well-attended workshops the applications of quantitative acoustical imaging in biology and medical applications, and in near-field imaging of materials, were discussed. Based on its cross-disciplinary aspects, the authors of the papers of AI27 present experiments, theory and construction of new instruments.
Download or read book Advances in Glass Science and Technology written by Vincenzo Maria Sglavo and published by BoD – Books on Demand. This book was released on 2018-06-06 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, some recent advances in glass science and technology are collected. In the first part, the structure and crystallization of innovative glass compositions are analysed. In the second part, innovative applications are described from the use of glass in optical devices and lasers to fibres in composites, micropatterned components in sensors and microdevices, beads in building walls and sealing in solid oxide fuel cells.
Download or read book Fabrication of Capacitive Micromachined Ultrasonic Transducers Based on Adhesive Wafer Bonding written by Zhenhao Li and published by . This book was released on 2017 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt: Capacitive micromachined ultrasonic transducers (CMUTs) can be used for medical imaging, non-destructive testing or medical treatment applications. It can also be used as gravimetric sensors for gas sensing or immersion bio-sensing. Although various CMUT fabrication methods have been reported, there are still many challenges to address. Conventional fabrication methods can be categorized as either surface micromachining or the wafer bonding method. These methods have design trade-offs and limitations associated with process complexity, structural parameter optimization and wafer materials selection. For example, surface micromachining approaches can suffer from complicated fabrication processes. In addition, structural parameters cannot be fully optimized due to feasibility concerns during fabrication. In contrast, the development of wafer bonding techniques enabled CMUTs to be fabricated in a straightforward way and structural parameters can be easily optimized when compared with a surface micromachining approach. However, the yield of the traditional wafer bonded CMUTs is very sensitive to contaminations and the surface quality at the bonding interface. Although the difficulties of the wafer bonding process are not always reported, they definitely exist for every researcher who wants to fabricate their own CMUTs. As a result, this dissertation work aims to develop a CMUT fabrication process with fewer fabrication constraints, low-cost and low process temperature for CMOS integration. The developed CMUT fabrication processes reported in the thesis applied photosensitive polymer adhesive for wafer bonding in order to make a process with good tolerance to contaminations and defects on the wafer surface, present a wide range of material selection at the bonding interface and require low process temperature (less than 250°C). These features can benefit CMUT fabrication with increased yield better design flexibility and lower cost. Having maximum process temperature of 250°C, the developed processes can also be CMOS compatible. Furthermore, a novel CMUT structure, which can only be achieved by the reported technique, was developed showing more than doubled ultrasound receive sensitivity when compared with conventional CMUT structures. The fabrication processes were developed systematically and the details of process development will be presented in this thesis.
Download or read book Electroceramic Based MEMS written by Nava Setter and published by Springer Science & Business Media. This book was released on 2006-03-30 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is focused on the use of functional oxide and nitride films to enlarge the application range of MEMS (microelectromechanical systems), including micro-sensors, micro-actuators, transducers, and electronic components for microwaves and optical communications systems. Applications, emerging applications, fabrication technology and functioning issues are presented and discussed. The book covers the following topics: Part A: Applications and devices with electroceramic-based MEMS: Chemical microsensors Microactuators based on thin films Micromachined ultrasonic transducers Thick-film piezoelectric and magnetostrictive devices Pyroelectric microsystems RF bulk acoustic wave resonators and filters High frequency tunable devices MEMS for optical functionality Part B: Materials, fabrication technology, and functionality: Ceramic thick films for MEMS Piezoelectric thin films for MEMS Materials and technology in thin films for tunable high frequency devices Permittivity, tunability and loss in ferroelectrics for reconfigurable high frequency electronics Microfabrication of piezoelectric MEMS Nano patterning methods for electroceramics Soft lithography emerging techniques The book is addressed to engineers, scientists and researchers of various disciplines, device engineers, materials engineers, chemists, physicists and microtechnologists who are working and/or interested in this fast growing and highly promising field. The publication of this book follows a Special Issue on electroceramic-based MEMS that was published in the Journal of Electroceramics at the beginning of 2004. The ten invited papers of that special issue were adapted by the authors into chapters of the present book and five additional chapters were added.
Download or read book The Design Fabrication and Characterization of Capacitive Micromachined Ultrasonic Transducers for Imaging Applications written by Andrew Stephan Logan and published by . This book was released on 2010 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt: Capacitive micromachined ultrasonic transducers (CMUTs) have proven themselves to be excellent candidates for medical ultrasonic imaging applications. The use of semiconductor fabrication techniques facilitates the fabrication of high quality arrays of uniform cells and elements, broad acoustic bandwidth, the potential to integrate the transducers with the necessary electronics, and the opportunity to exploit the benefits of batch fabrication. In this thesis, the design, fabrication and testing of one- and two-dimensional CMUT arrays using a novel wafer bonding process whereby the membrane and the insulation layer are both silicon nitride is reported. A user-grown insulating membrane layer avoids the need for expensive SOI wafers, permits optimization of the electrode size, and allows more freedom in selecting the membrane thickness, while also enjoying the benefits of wafer bonding fabrication. Using a row-column addressing scheme for an NxN two-dimensional array permits three-dimensional imaging with a large reduction in the complexity of the array when compared to a conventional 2D array with connections to all N2 elements. Only 2N connections are required and the image acquisition rate has the potential to be greatly increased. A simplification of the device at the imaging end will facilitate the integration of a three-dimensional imaging CMUT array into either an endoscope or catheter which is the ultimate purpose of this research project. To date, many sizes of transducers which operate at different frequencies have been successfully fabricated. Initial characterization in terms of resonant frequency and, transmission and reception in immersion has been performed on most of the device types. Extensive characterization has been performed with a linear 32 element array transducer and a 32x32 element row-column transducer. Two- and three-dimensional phased array imaging has been demonstrated.
Download or read book Capacitive Micromachined Ultrasonic Transducers with Substrate embedded Springs written by Byung Chul Lee and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: After the first capacitive micromachined ultrasonic transducer (CMUT) was invented in 1994, it became one of the candidate technologies to advance the state-of-the-art of medical ultrasound imaging. Benefiting from its fabrication technique based on the semiconductor industry, CMUT technology has broadened the medical and therapeutic applications such as real-time volumetric ultrasound imaging, catheter-based forward-looking intravascular ultrasound (IVUS), photoacoustic imaging, high-intensity focused ultrasound (HIFU) and so on. In spite of many advantages, however, CMUT technology has been criticized with its relatively low transmit sensitivity (~10 kPa/V) or low average volume displacement efficiency (0.1 nm/V) as well as large drive and bias voltage requirements (in a range of a few hundreds of volts). In order to resolve these issues and open up new potential of clinical applications, this dissertation describes the design, fabrication, and system implementation of CMUTs with substrate-embedded springs, so-called post-CMUT (PCMUT). Since PCMUT structure resembles an ideal piston transducer, the improvements in performance mainly stem from the higher average displacement of the top plate for a given gap height. The overview of the first generation PCMUT is introduced and two main issues in simulation and fabrication aspects of the first generation PCMUT is discussed. To further improve the PCMUT device, a 3D finite element analysis (FEA) model of the PCMUT is demonstrated to predict the performance of the first generation PCMUT. In addition, the design guideline of the second generation PCMUT is proposed for achieving the maximum fractional bandwidth (100 %) as well as with the highest transmit sensitivity (~28 kPa/V). The second generation PCMUT is fabricated by using three combination MEMS processes: usage of two silicon-on-insulator (SOI) wafers, wafer bonding process, and wafer polishing process. The second generation PCMUT achieves high transmit sensitivity (~21 kPa/V) or large average volume displacement efficiency (1.1 nm/V) with a low bias voltage (55 V). Compared to a commercial piezoelectric transducer, the second generation PCMUT improves 2.75 times of the maximum output pressure and 5.25 times of the average volume displacement efficiency with respect to the same voltage. After fabrication and performance characterization of the second generation PCMUT, this dissertation demonstrates the feasibility of PCMUT to use it in medical imaging system by integrating PCMUT with a custom-built integrated circuit (IC). Photoacoustic imaging is also presented for one of its application examples.
Download or read book Medical Imaging written by Krzysztof Iniewski and published by John Wiley & Sons. This book was released on 2009-02-18 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: A must-read for anyone working in electronics in the healthcare sector This one-of-a-kind book addresses state-of-the-art integrated circuit design in the context of medical imaging of the human body. It explores new opportunities in ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), nuclear medicine (PET, SPECT), emerging detector technologies, circuit design techniques, new materials, and innovative system approaches. Divided into four clear parts and with contributions from a panel of international experts, Medical Imaging systematically covers: X-ray imaging and computed tomography–X-ray and CT imaging principles; Active Matrix Flat Panel Imagers (AMFPI) for diagnostic medical imaging applications; photon counting and integrating readout circuits; noise coupling in digital X-ray imaging Nuclear medicine–SPECT and PET imaging principles; low-noise electronics for radiation sensors Ultrasound imaging–Electronics for diagnostic ultrasonic imaging Magnetic resonance imaging–Magnetic resonance imaging principles; MRI technology
Download or read book Capacitive Micromachined Ultrasonic Transducers CMUTs for Humidity Sensing written by Zhou Zheng and published by . This book was released on 2019 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last two decades, capacitive micromachined ultrasonic transducers (CMUTs) have proven themselves to be promising for various ultrasound imaging and chemical sensing applications. Although holding many benefits for ultrasound imaging, CMUTs have certain weaknesses such as the relatively low output pressure at transmission, which hinder their development in the diagnostic imaging application. In the sensing area, CMUTs have shown attractive features such as high mass sensitivity, miniaturized array configuration, and ease of functionalization. However, their potential for humidity sensing is less explored. The objectives of this thesis lie in two aspects. One is to offer a solution to overcome the limitation of low output pressure, and the other is to develop CMUTs as resonant gravimetric humidity sensors. The major efforts are made on the second task. For the first objective, a novel dual-element ultrasonic transducer is proposed. It incorporates two transducer technologies by using a circular piezoelectric element for ultrasound transmission and an annular CMUT element for reception. The hybrid transducer combines the broad bandwidth and high receive sensitivity of the CMUT and the high output power of the piezoelectric transducer to improve the overall sensitivity and axial resolution. The annular CMUT is designed, fabricated, and concentrically aligned with the piezoelectric probe via a custom housing. Immersion measurements show that the hybrid dual-element transducer improves the axial resolution by 25.58% and the signal-to-noise ratio by 8.55 dB over the commercial piezoelectric probe. For the second objective, a CMUT-based resonant humidity sensor is first developed with the direct wafer bonding technique. Graphene oxide (GO) is employed as the sensing material. Due to combination of the mass-sensitive CMUT and the moisture-sensitive GO, the sensor exhibits rapid response/recovery, good repeatability, and higher sensitivity than most of its competitors. The second generation of CMUT-based humidity sensors aims to further improve the relative humidity (RH) sensing performance by adopting the nitride-to-oxide wafer bonding technology for CMUT fabrication. In contrast to conventional wafer bonding CMUT processes that use expensive silicon-on-insulator (SOI) wafers to produce resonating membranes, the new process employs low-pressure chemical vapor deposition (LPCVD) silicon nitride as the membrane material. It provides thinner and lighter membranes, and thus more sensitive CMUT resonators. Additional benefits of the nitride-to-oxide wafer bonding technique are the reduced fabrication complexity and more controllable membrane thickness. Finally, a dual-frequency (10/14 MHz) CMUT is developed using this fabrication technique. It generates two RH response curves and can provide more accurate RH sensing. Due to the independence of the two resonance frequencies, the dual-frequency CMUT also shows great potential for identification of different chemicals. This thesis demonstrates that CMUT sensors can be strong candidates for miniaturized, highly sensitive, and reliable humidity sensors.
