Design and simulation of high sensitive capacitive pressure sensor with slotted diaphragm

This paper presents a high sensitive MEMS capacitive pressure sensor for biomedical applications. Two sensor designs incorporating clamped and slotted diaphragm are implemented and compared to realize the pressure-sensitive components. The pressure sensor has been designed to measure pressures in the range of 0 to 60 mmhg that is in the range of intraocular pressure sensors. Intraocular pressure sensors are important in detection and treatment of an incurable disease called glaucoma. The capacitive pressure sensor is formed using p++ silicon diaphragm as a biocompatible material. The novelty of this method relies on p++si diaphragm includes some slots to reduce the effect of residual stress and stiffness of diaphragm. The slotted diaphragm makes capacitive pressure sensor more sensitive. That is more suitable for measuring intraocular pressure sensor. The results yield a sensitivity of 1.811×10-5 1/Pa for the clamped and 5.96×10-5 1/Pa for the slotted pressure sensor with a 0.55 × 0.55 mm2 diaphragm. Furthermore, the pull-in voltage for the clamped pressure sensor is 51v, while the pull-in voltage of the slotted one is 38v.

[1]  R. Moses.  The Goldmann applanation tonometer. , 1958, American journal of ophthalmology.

[2]  K. Wise,et al.  Pressure sensitivity in anisotropically etched thin-diaphragm pressure sensors , 1979, IEEE Transactions on Electron Devices.

[3]  K.D. Wise,et al.  Scaling limits in batch-fabricated silicon pressure sensors , 1987, IEEE Transactions on Electron Devices.

[4]  J. H. Jerman.  The fabrication and use of micromachined corrugated silicon diaphragms , 1990 .

[5]  J Katz,et al.  A population-based evaluation of glaucoma screening: the Baltimore Eye Survey. , 1991, American journal of epidemiology.

[6]  Khalil Najafi,et al.  Internal stress compensation and scaling in ultrasensitive silicon pressure sensors , 1992 .

[7]  L. Titcomb.  TREATMENT OF GLAUCOMA : PART 1 , 1999 .

[8]  S. Senturia.  Microsystem Design , 2000 .

[9]  Bernardo Tellini,et al.  Design of a system for continuous intraocular pressure monitoring , 2004, IEEE Transactions on Instrumentation and Measurement.

[10]  E. Meng,et al.  Implantable parylene MEMS for glaucoma therapy , 2005, 2005 3rd IEEE/EMBS Special Topic Conference on Microtechnology in Medicine and Biology.

[11]  Qing-An Huang,et al.  A novel capacitive pressure sensor based on sandwich structures , 2005, Journal of Microelectromechanical Systems.

[12]  K. Katuri,et al.  Intraocular Pressure Monitoring Sensors , 2008, IEEE Sensors Journal.

[13]  Kalyan C. Katuri,et al.  A surface micromachined capacitive pressure sensor for intraocular pressure measurement , 2010, Proceedings of 2010 IEEE/ASME International Conference on Mechatronic and Embedded Systems and Applications.

[14]  N. Yazdi,et al.  A high-sensitive ultra-thin MEMS capacitive pressure sensor , 2011, 2011 16th International Solid-State Sensors, Actuators and Microsystems Conference.