Capacitative micromachined Ultrasonic transducers, manufactured using standard semiconductor fabrication techniques have received a lot of interest over recent years. Working in collaboration with Qinetiq we have a number projects in this area, working with devices using standard CMOS processes. These devices vary in dimension from 0.100-5mm area, somewhat larger than those reported elsewhere, with membrane thickness from 0.5-2µm.
Current research is concerned characterising arrays of devices machined on the same substrate for use as as passive 2-D arrays for imaging, active 1-D phased arrays and as apodised imersion transducers..
R.A. Noble, A.R.D. Jones, T.J. Robertson, D.A. Hutchins and D.R. Billson, "Novel wide bandwidth micromachined ultrasonic transducers", IEEE Trans. Ultras. Ferr. Freq. Contr. 48, 1495-1507 (2001)