IEEE International Ultrasonics Symposium, Hawaii, Amerika Birleşik Devletleri, 5 - 08 Ekim 2003, ss.1161-1164
We report experimental results from collapsed regime operation of capacitive micromachined ultrasonic transducers (cMUTs) fabricated by a wafer bonding technique. The results show that a cMUT operating in the collapsed regime produces a maximal output pressure higher than a cMUT operating in the pre-collapse regime at 90 % of its collapse voltage, 1.79 kPa/V vs. 9.72 kPa/V at 2.3 MHz. In collapsed regime operation the fractional bandwidth (pulse echo) is increased compared to that obtained in pre-collapsed regime operation 140 % vs. 83 % with a bias 90 % of the collapse voltage. Characterization of 1-D cMUT arrays operating in oil was done by ultrasonic pulse echo and pitch catch measurements.