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

fYear

2008

fDate

2-5 Nov. 2008

Firstpage

504

Lastpage

507

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 Q_air and Q_support. We investigated these two factors independently. We calculate Q_air of circular silicon membrane analytically, and numerically. Calculated Q_air is compared to measured value. In order to find Q_support empirically, we measured quality factor of CMUT in vacuum chamber. Q_air is proportional to (radius/thickness)^-2 and Q_support 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;

fLanguage

English

Publisher

ieee

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

Type

conf

DOI

10.1109/ULTSYM.2008.0123

Filename

4803684