7. Advancements on Silicon Ultrasound Probes (CMUT) for Medical Imaging Applications

Capacitive micromachined ultrasonic transducers (CMUTs) are micro-electromechanical devices (MEMS) fabricated using silicon micromachining techniques. The interest of this technology relies in its full compatibility with the microelectronic technology that makes possible to integrate on the same chip the transducer and the controlling/conditioning electronics, so as to achieve low-cost and high-performance devices. The design and fabrication of a 192-element linear array CMUT probe operating in the range 6–18 MHz is here presented. The CMUT array is micro-fabricated and packed using a novel fabrication concept specifically conceived for imaging transducer arrays. The performance optimization of the probe is performed by connecting the CMUT array with multichannel analog front-end electronic circuits housed into the probe body. Characterization and imaging results are used to assess the performance of CMUTs with respect to conventional piezoelectric transducers. This paper is a review on the activities of our group in this field.