Axial asymmetry for improved sensitivity in MEMS piezoresistors

The strain induced resistance change is compared for asymmetric, symmetric and diffused piezoresistive elements. Finite element analysis is used to simulate the performance of a T-shaped piezoresistive MEMS cantilever, including a lumped parameter model to show the effect of geometric asymmetry on the piezoresistor sensitivity. Asymmetric piezoresistors are found to be much more sensitive to applied load than the typical symmetric design producing about two orders of magnitude higher resistance change. This is shown to be due to the difference in the stress distribution in the symmetric and asymmetric geometries resulting in less resistance change cancellation in the asymmetric design. Although still less sensitive than diffused piezoresistors, asymmetric piezoresistors are sensitive enough for many applications, and are much easier to fabricate and integrate into MEMS devices.

[1]  A Computational Approach for Simulating P-type Silicon Piezoresistor Using Four Point Bending Setup , 2013 .

[2]  C. Quate,et al.  Atomic resolution with an atomic force microscope using piezoresistive detection , 1993 .

[3]  Minhang Bao,et al.  A piezoresistive accelerometer with a novel vertical beam structure , 1997, Proceedings of International Solid State Sensors and Actuators Conference (Transducers '97).

[4]  R. Kakoschke,et al.  Trench sidewall implantation with a parallel scanned ion beam , 1990 .

[5]  Y. Kanda,et al.  A graphical representation of the piezoresistance coefficients in silicon , 1982, IEEE Transactions on Electron Devices.

[6]  Gotszalk,et al.  Piezoresistive sensors for scanning probe microscopy , 2000, Ultramicroscopy.

[7]  Yozo Kanda,et al.  Nonlinearity of piezoresistance effect in p- and n-Type silicon , 1990 .

[8]  Bruce W. Alphenaar,et al.  Viscous damping of microresonators for gas composition analysis , 2006 .

[9]  G. E. J. Koops,et al.  Piezoresistive ring-shaped MEMS resonator , 2009, TRANSDUCERS 2009 - 2009 International Solid-State Sensors, Actuators and Microsystems Conference.

[10]  Isao Shimoyama,et al.  triaxial tactile sensor without crosstalk using pairs of piezoresistive beams ith sidewall doping , 2013 .

[11]  K. Walsh,et al.  Development of Ultra-Miniature Pressure Sensors for 1-French Biomedical Applications and Beyond , 2008 .

[12]  Zhao Yulong,et al.  An improved structural design for accelerometers based on cantilever beam‐mass structure , 2012 .

[13]  Yozo Kanda,et al.  Piezoresistance effect of silicon , 1991 .

[14]  Lutz Doering,et al.  Piezoresistive cantilever as portable micro force calibration standard , 2003 .

[15]  Tetsuo Kan,et al.  Design of a piezoresistive triaxial force sensor probe using the sidewall doping method , 2013 .

[16]  Thomas W. Kenny,et al.  Independent detection of vertical and lateral forces with a sidewall-implanted dual-axis piezoresistive cantilever , 1998 .

[17]  A Microgyroscope With Piezoresistance for Both High-Performance Coriolis-Effect Detection and Seesaw-Like Vibration Control , 2006, Journal of Microelectromechanical Systems.

[18]  Christian Bergaud,et al.  Fabrication of biological microarrays using microcantilevers , 2003 .

[19]  Suzuki,et al.  Origin of the shear piezoresistance coefficient pi 44 of n-type silicon. , 1991, Physical review. B, Condensed matter.

[20]  Helmut Seidel,et al.  Resonant accelerometer with self-test , 2001 .

[21]  Gijsbertus J.M. Krijnen,et al.  Micromachined fountain pen for atomic force microscope-based nanopatterning , 2004 .

[22]  Shinji Odanaka,et al.  Depth Profiles of Boron Atoms with Large Tilt‐Angle Implantations , 1986 .

[23]  Guifu Ding,et al.  Microfabricated Quill-Type Surface Patterning Tools for the Creation of Biological Micro/Nano Arrays , 2004, Biomedical microdevices.

[24]  S. Sugiyama,et al.  Ultra miniature novel three-axis micro accelerometer , 2009, 2009 IEEE Sensors.

[25]  Chi-Hang Chin,et al.  A Low-Voltage CMOS-Microelectromechanical Systems Thermal-Piezoresistive Resonator With $Q > 10\,000$ , 2015, IEEE Electron Device Letters.

[26]  Y. Kanda,et al.  Piezoresistance Effect in p‐Type Silicon , 2005 .

[27]  P. C. Fletcher,et al.  Piezoresistive geometry for maximizing microcantilever array sensitivity , 2008, 2008 IEEE Sensors.

[28]  Liviu Nicu,et al.  A Closed-loop MEMS-based Spotter Integrating Position Sensors with Nanometric Precision for the Control of Droplet Uniformity , 2006, 2006 1st IEEE International Conference on Nano/Micro Engineered and Molecular Systems.

[29]  Thierry Leichle,et al.  Bioplume : a MEMS-based picoliter droplet dispenser with electrospotting means for patterning surfaces at the micro- and the nanometer scales , 2005 .

[30]  F. Rossi,et al.  Nanostructuring surfaces with conjugated silica colloids deposited using silicon-based microcantilevers , 2005 .

[31]  Dzung Viet Dao,et al.  Simulation, fabrication and characterization of a three-axis piezoresistive accelerometer , 2006 .

[32]  Charles S. Smith.  Piezoresistance Effect in Germanium and Silicon , 1954 .