Title :
A surface-micromachined MEMS acoustic sensor with X-shape bottom electrode anchor
Author :
Lee, Jaewoo ; Ko, S.C. ; Je, C.H. ; Lee, M.L. ; Choi, C.-A. ; Yang, Y.S. ; Heo, S. ; Kim, Jongdae
Author_Institution :
Adv. i-MEMS team, Electron. & Telecommun. Res. Inst., Daejeon, South Korea
Abstract :
A surface-micromachined capacitive-type micro-electro-mechanical system (MEMS) acoustic sensor with X-shape bottom electrode anchor on a Si substrate is presented. As it is designed to be implemented on only one side of a substrate for a simple monolithic integrated process, this sensor has X-shape bottom electrode anchor fabricated. The anchor operates to remove the back side process of wafer for a conventional back chamber because the chamber is formed through Si surface etching by an isotropic dry etcher of XeF2. The Si MEMS acoustic sensor proposed in this paper has a diameter of 300 ¿m and a back chamber depth of 25 ¿m. It shows a pull down voltage of 9.1 V at 1 kHz and a zero-bias capacitance of 1.87 pF. Additionally, the sensor has an open-circuit sensitivity of 0.57 mV/Pa at 1 kHz on a bias of 5 V.
Keywords :
CMOS integrated circuits; capacitive sensors; electrodes; elemental semiconductors; etching; micromachining; microsensors; silicon; surface acoustic wave transducers; CMOS process; MEMS acoustic sensor; Si; X-shape bottom electrode anchor; capacitance 1.87 pF; capacitive-type acoustic sensor; depth 25 mum; frequency 1 kHz; isotropic dry etcher; microelectromechanical system acoustic sensor; monolithic integrated process; open-circuit sensitivity; size 300 mum; surface micromachining; voltage 9.1 V; Acoustic sensors; Biomembranes; CMOS integrated circuits; CMOS process; Dry etching; Electrodes; Fabrication; Micromechanical devices; Microphones; Sensor phenomena and characterization;
Conference_Titel :
Sensors, 2009 IEEE
Conference_Location :
Christchurch
Print_ISBN :
978-1-4244-4548-6
Electronic_ISBN :
1930-0395
DOI :
10.1109/ICSENS.2009.5398401
