Micromachined ultrasound transducers for fluids and gases

With a special micromachining process ultrasound transducers can be realize d within a standard CMOS microelectronic process, allowing the monolithic i ntegration? of microelectronics and micromechanics on a single chip. The el ectrostatic transducer is formed by an army of membranes. For air-ultrasonics ics a bulk-micromachining-process was developed which i s best suited for transducers with operating frequencies below I MHz.