Abstract
In this paper a novel single-chip microelectromechanical systems (MEMS) capacitive fingerprint sensor with slotted membrane is developed to improve the sensitivity. The capacitive sensor consists of a thin, flexible membrane and a rigid back plate with air gap. In this study with making slots in upper electrode to decrease the mechanical stiffness of the membrane, using proportional T-shaped protrusion on diaphragm in order to concentrate the force from finger ridges, making holes in lower electrode to reduce the air damping and using low stress material for diaphragm, we have been succeeded to design a novel MEMS fingerprint sensor with high sensitivity compared with the previous works (Sato et al., IEEE Trans Electron Devices 52:1026–1032, 2005; Damghanian and Majlis, 2008 IEEE International Conference on Semiconductor Electronics (ICSE 2008), pp 634–638 2008). The behaviors of the fingerprint sensor with clamped and slotted membranes are analyzed using the finite element method (FEM). The results yield a sensitivity of 1.44 fF/Mpa for the clamped and 3.22 fF/Mpa for the slotted fingerprint sensor with a 50 × 50 μm2 diaphragm. The sensitivity of the slotted structure is increased 2.236 times.
Similar content being viewed by others
References
Chowdhury S, Jullien GA, Ahmadi MA, Miller WC, (2001) A MEMS implementation of an acoustical sensor array. In: IEEE international symposium, pp 273–276
Chowdhury S, Ahmadi M, Miller WC (2002) Design of a MEMS acoustical beamforming sensor microarray. IEEE Sens J 2(6):617–627
Damghanian M, Majlis BY, (2006) Design of a high sensitivity structure for mems fingerprint sensor, 2006 IEEE international conference on semiconductor electronics (ICSE 2006), pp 177–184
Damghanian M, Majlis BY (2008) A modified lift-off technique to prevent pattern following effect in microfabrication, 2008 IEEE international conference on semiconductor electronics (ICSE 2008), pp 634–638
De Souza RJ, Wise KD (1997) A very high density bulk micromachined capacitive tactile imager. Solid state sensors and actuators. Transducers’97 2:1473–1476
Ganji BA, Majlis BY (2008) Analytical analysis of flat and corrugated membranes for MEMS capacitive sensors. Int J Nonlinear Dynamics Eng Sci 1(1):47–57
Ganji BA, Nateri MS (2010) Fabrication of a novel mems capacitive microphone using lateral slotted diaphragm, IJE Trans B Appl 23, Nos. 3 & 4, pp 191–200
Henry ER (1900) Classification and uses of finger prints. George Rutledge & Sons, Ltd., London
Jermam JH (2001) The fabrication and use of micromachined corrugated silicon diaphragms. Sens Actuators A21-A23:988–992
Jing C, Litian L, Zhijian L (2001) Dynamic characteristics of novel single-chip fabricated corrugated diaphragms for micro-acoustic devices. IEEE pp 757–760
Kressmann R, Mlaiber M (2002) Silicon condenser microphones with corrugated silicon oxide/nitride electret membranes. Sens Actuators A 100:301–309
Machida K, Shigematsu S, Morimura H, Tanabe Y, Sato N, Shimoyama N, Kumazaki T, Kudou K, Yano M, Kyuragi H (2001) A novel semiconductor capacitive sensor for a single chip LSI fingerprint sensor/identifier. IEEE Trans Electron Devices 48(10):2273–2278
Sato N, Shigematsu S, Morimura H, Yano M, Kudou K, Kamei T, Machida K (2005) Novel surface structure and its fabrication process for MEMS fingerprint sensor. IEEE Trans Electron Devices 52(5):1026–1032
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Ganji, B.A., Nateri, M.S. A high sensitive MEMS capacitive fingerprint sensor using slotted membrane. Microsyst Technol 19, 121–129 (2013). https://doi.org/10.1007/s00542-012-1647-1
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00542-012-1647-1