Title :
Optimum design of circular CMUT membranes for high quality factor in air
Author :
Park, K.K. ; Lee, H.J. ; Crisman, P. ; Kupnik, M. ; Oralkan, Ö ; Khuri-Yakub, B.T.
Author_Institution :
Edward L. Ginzton Lab., Stanford Univ., Stanford, CA
Abstract :
This paper presents optimum design of circular membrane for high quality factor. A quality factor of CMUT, we designed for resonant chemical sensor, is dominated by Qair and Qsupport. We investigated these two factors independently. We calculate Qair of circular silicon membrane analytically, and numerically. Calculated Qair is compared to measured value. In order to find Qsupport empirically, we measured quality factor of CMUT in vacuum chamber. Qair is proportional to (radius/thickness)-2 and Qsupport is proportional to (radius/thickness)3. Thus the optimum aspect ratio of membrane exists for maximum quality factor.
Keywords :
Q-factor; capacitive sensors; chemical sensors; elemental semiconductors; membranes; micromachining; microsensors; silicon; ultrasonic transducers; Si; aspect ratio; capacitive micromachined ultrasonic transducer; circular CMUT membrane; quality factor; resonant chemical sensor; silicon membrane; vacuum chamber; Biomembranes; Chemical sensors; Impedance; Low-frequency noise; Noise level; Phase noise; Q factor; Resonance; Resonant frequency; Silicon; Air damping; CMUT; Circular membrane; Quality factor; component;
Conference_Titel :
Ultrasonics Symposium, 2008. IUS 2008. IEEE
Conference_Location :
Beijing
Print_ISBN :
978-1-4244-2428-3
Electronic_ISBN :
978-1-4244-2480-1
DOI :
10.1109/ULTSYM.2008.0123
