Presented is the configuration design for piezoresistive absolute micropressure sensors. A figure of merit called the performance factor (PF) is defined as a quantitative index to describe the comprehensive performances of a sensor including sensitivity, resonant frequency and acceleration interference. Two configurations are proposed through introducing islands and sensitive beams into the typical flat diaphragm. The stress distributions of sensitive elements are analysed by a finite element method. Multivariate fittings based on ANSYS simulation results are performed to establish the equations on surface stresses and deflections of the two sensors. Optimisation by MATLAB is carried out to determine the dimensions of the configurations. Convex corner undercutting is analysed to estimate the final dimensions of the islands. Each PF of the two configurations with the determined dimensions has been calculated and compared. Silicon bulk micromachining is utilised to fabricate the prototypes of the sensors. The outputs of the sensors under both static and dynamic conditions are tested. Experimental results reveal that the configuration with quad islands presents the highest PF of 210.947 Hz^1/4. The favourable overall performances make the sensor more suitable for altimetry.

References

1. 1)
  - L. Lin , H.-C. Chu , Y.-W. Lu . A simulation program for the sensitivity and linearity of piezoresistive pressure sensors. J. Microelectromech. Syst. , 4 , 514 - 522
2. 2)
  - 15. Tufte, O.N., Stelzer, E.L.: ‘Piezoresistive properties of silicon diffused layers’, J. Appl. Phys., 1963, 34, (2), pp. 313–318 (doi: 10.1063/1.1702605).
3. 3)
  - 4. Gradolph, C., Friedberger, A., Muller, G., Wilde, J.: ‘Impact of high-g and high vibration environments on piezoresistive pressure sensor performance’, Sens. Actuators A, Phys., 2009, 150, (1), pp. 69–77 (doi: 10.1016/j.sna.2008.12.007).
4. 4)
  - 10. Clark, S.K., Wise, K.D.: ‘Pressure sensitivity in anisotropically etched thin diaphragm pressure sensors’, IEEE Trans. Electron Devices, 1979, 26, (12), pp. 1887–1896 (doi: 10.1109/T-ED.1979.19792).
5. 5)
  - 12. Hopcroft, M.A., Nix, W.D., Kenny, T.W.: ‘What is the Young's modulus of silicon?’, J. Microelectromech. Syst., 2010, 19, (2), pp. 229–238 (doi: 10.1109/JMEMS.2009.2039697).
6. 6)
  - B. Tian , Y.L. Zhao , Z.D. Jiang . The design and analysis of beam-membrane structure sensors for micropressure measurement. Rev. Sci. Instrum. , 4
7. 7)
  - 13. Timoshenko, S., Woinosky-Krieger, S.: ‘Theory of plates and shells’ (McGraw Hill Classic Textbook, New York, 1987, 2nd edn).
8. 8)
  - 6. Shimazoe, M., Matsuoka, Y., Yasukawa, A., Tanabe, M.: ‘A special silicon diaphragm pressure sensor with high output and high-accuracy’, Sens. Actuators, 1982, 2, (3), pp. 275–282.
9. 9)
  - Q. Wang , J. Ding , W. Wang . Fabrication and temperature coefficient compensation technology of low cost high temperature pressure sensor. Sens. Actuators A, Phys. , 2 , 468 - 473
10. 10)
  - G. Zhang , L. Zhao , Z. Jiang . Surface stress-induced deflection of a microcantilever with various widths and overall microcantilever sensitivity enhancement via geometry modification. J. Phys. D, Appl. Phys.
11. 11)
  - 10. Johnson, R.H., Karbassi, S., Sridhar, U., Speldrich, B.: ‘A high sensitivity ribbed and bossed pressure transducer’, Sens. Actuators A, 1993, 35, (2), pp. 93–99 (doi: 10.1016/0924-4247(92)80146-T).
12. 12)
  - 11. Young, W.C.: ‘Roark's formulas for stress and strain’ (McGraw-Hill, New York, 1986, 6th edn), pp. 440–464.
13. 13)
  - 7. Bao, M.H., Yu, L.Z., Wang, Y.: ‘Micromachined beam-diaphragm structure improves performances of pressure transducer’, Sens. Actuators A, Phys., 1990, 21, (1–3), pp. 137–141 (doi: 10.1016/0924-4247(90)85026-Z).
14. 14)
  - 14. Fan, W., Zhang, D.C.: ‘A simple approach to convex corner compensation in anisotropic KOH etching on a (100) silicon wafer’, J. Micromech. Microeng., 2006, 16, (10), pp. 1951–1957 (doi: 10.1088/0960-1317/16/10/006).
15. 15)
  - 2. Mackowiak, P., Schiffer, M., Xin, X., Obermeier, E., Ha-Duong, N.: ‘Design and simulation of ultra high sensitive piezoresistive MEMS sensor with structured membrane for low pressure applications’. 12th Electronics Packaging Technology Conf. (EPTC 2010), Singapore, 2010, pp. 757–761.

Configuration improvement for micropressure sensor with vibration interference

References

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