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Collapsed regime operation of capacitive micromachined ultrasonic transducers based on wafer-bonding technique

2003-01-01
Huang, Y
Haeggstrom, E
Bayram, Barış
Zhuang, X
Ergun, AS
Cheng, CH
Khuri-Yakub, BT
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.