Diamond-based capacitive micromachined ultrasonic transducers

作者：Bayram Baris^*

来源：Diamond and Related Materials, 2012, 22: 6-11.

DOI：10.1016/j.diamond.2011.11.006

• Capacitive micromachined ultrasonic transducer
• Ultrananocrystalline diamond
• Plasma-activated direct bonding
• Microelectromechanical devices

Capacitive micromachined ultrasonic transducers (CMUTs) employing diamond membranes are demonstrated. The design, finite element modeling, microfabrication, and experimental characterization of diamondbased CMUTs are reported. Ultrananocrystalline diamond having a chemical mechanical polished silicon dioxide interlayer deposited via high temperature oxide (HTO) process at 850 degrees C in a low pressure chemical vapor deposition (LPCVD) furnace is employed as the membrane to form vacuum sealed cavities using plasma-activated direct bonding technology. Electrical impedance, deflection, and transmission measurements of a fabricated CMUT are performed in air using an impedance analyzer, a white light interferometer and a hydrophone, respectively. Experimental results verify the accuracy of finite element modeling. Diamond-based CMUTs possess 3-dB fractional bandwidth of 3% at a center frequency of 1.74 MHz in air. Our experimental results demonstrate diamond as an alternate membrane material for CMUTs, and that diamond can be employed in novel microelectromechanical devices.

• 出版日期2012-2