Xiaoning Jiang

In this monograph, the authors reports the current advancement in high frequency piezoelectric crystal micromachined ultrasound transducers and arrays and their biomedical applications. Piezoelectric ultrasound transducers operating at high frequencies (> 20 MHz) are of increasing demand in recent years for medical imaging and biological particle manipulation involved therapy. The performances of transducers greatly rely on the properties of the piezoelectric materials and transduction structures, including piezoelectric coefficient (d), electromechanical coupling coefficient (k), dielectric permittivity (e) and acoustic impedance (Z). Piezo-composite structures are preferred because of their relatively high electromechanical coupling coefficient and low acoustic impedance. A number of piezo-composite techniques have been developed, namely “dice and fill,” “tape-casting,” “stack and bond,” “interdigital phase bonding,” “laser micromachining” and “micro-molding”. However, these techniques are either difficult to achieve fine features or not suitable for manufacturing of high frequency ultrasound transducers (> 20 MHz). The piezo-composite micromachined ultrasound transducers (PC-MUT) technique discovered over the last 10 years or so has demonstrated high performance high frequency piezo-composite ultrasound transducers. In this monograph, piezoelectric materials used for high frequency transducers is introduced first. Next, the benefits and theory of piezo composites is presented, followed by the design criteria and fabrication methods. Biomedical applications using piezo composites micromachined ultrasound transducers (PC-MUT) and arrays will also be reported, in comparison with other ultrasound transducer techniques. The final part of this monograph describes challenges and future perspectives of this technique for biomedical applications.

The application of MEMS (micro-electro-mechanical systems) in such diverse fields as intelligent microsensors, data storage, biomedical engineering and wireless communication is booming. Focusing on microstereolithography, this timely work provides insight into state-of-the-art microfabrication techniques for 3D microstructures, microdevices and MEMS. * A unique and accessible overview of micro-system manufacture using the latest semiconductor processing techniques * Coverage of the developmental history of MEMS, micro-sensors, actuators and signal processing units. * Insight to a range of microfabrication techniques from laser ablation to x-ray lithography, silicon micro-machining and micro-moulding. * Describes the latest fabrication prototypes and applications, including thin-film transistors, antennas, wireless telemetry systems and transducers Microelectronics engineers will profit form this detailed overview of current technologies. Material technologists and physicists working in industrial and academic research and development will also find this a valuable reference source.