Hostname: page-component-78c5997874-fbnjt Total loading time: 0 Render date: 2024-11-19T06:00:49.706Z Has data issue: false hasContentIssue false
  • English
  • Français

Titanium-Nickel Shape Memory Thin Film Actuators for Micromachined Valves

Published online by Cambridge University Press:  15 February 2011

H. Kahn ,
W. L. Benard ,
M. A. Huff  and
A. H. Heuer
H. Kahn
Affiliation:
Department of Materials Science and Engineering
W. L. Benard
Affiliation:
Department of Electrical Engineering and Applied Physics, Case Western Reserve University, Cleveland, Ohio 44106
M. A. Huff
Affiliation:
Department of Electrical Engineering and Applied Physics, Case Western Reserve University, Cleveland, Ohio 44106
A. H. Heuer
Affiliation:
Department of Materials Science and Engineering
Get access

Abstract

Microelectromechanical valves have been fabricated from silicon wafers using standard bulk micromachining techniques, which utilize thin (2 μm) films of sputter-deposited titaniumnickel as the actuators. The TiNi shape memory alloy actuators are thermally driven by resistive heating, through the passage of an electric current. TiNi diaphragms (8.4 mm wide) are fabricated and tested in a pressure-temperature controlled fixture in order to determine the mechanical properties of the shape memory film. If a silicon island is left attached to the center of the diaphragm, this can act as a “boss” whose movement against an orifice will open and close the valve. The orifice can be etched into a second silicon wafer or machined from another rigid material. Use of mechanical spacers and external bias springs result in a normally-closed or normally-open configuration. Modulations of up to 90 percent have been observed in gas flows of up to 0.6 liter/min. Water flows as high as 5 ml/min. have been modulated by 60 percent.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 444: Symposium I – Materials for Mechanical and Optical Microsystems , 1996 , 227
Copyright
Copyright © Materials Research Society 1997

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Bosch, D., Heimhofer, B., Muck, G., Seidel, H., Thumser, U., and Welser, W., “A silicon microvalve with combined electromagnetic/electrostatic actuation,” Sensors and Actuators A, 37–38, 684 (1993).Google Scholar
2. Ohnstein, T., Fukiura, T., Ridley, J., and Bonne, U., “Micromachined silicon microvalve,” Proc. IEEE Micro-electro-mechanical Systems Workshop, 95 (1990).Google Scholar
3. Huff, M.A., Mettner, M.S., Lober, T.A., and Schmidt, M.A., “A pressure-balanced electrostatically-actuated microvalve,” Proc. IEEE Solid State Sensors and Actuators Workshop, 123 (1990).Google Scholar
4. Popescu, D.S., Dascalu, D.C., Elwenspoek, M., and Lammerink, T., “Silicon active microvalves using buckled membranes for actuation,” Proc. IEEE Transducers 95, 305 (1995).Google Scholar
5. Sato, K. and Shikida, M., “An electrostatically actuated gas valve with an S-shaped film element,” J Micromech. Microeng., 4, 205 (1994).Google Scholar
6. Lisec, T., Hoerschelmann, S., Quenzer, H.J., Wagner, B., and Benecke, W., “Thermally driven microvalve with buckling behaviour for pneumatic applications, Proc. IEEE Micro-electromechanical Systems Workshop, 13 (1994).Google Scholar
7. Barth, P.W., Beatty, C.C., Field, L.A., Baker, J.W., and Gordon, G.B., “A robust normallyclosed silicon microvalve,” Proc. IEEE Solid State Sensors and Actuators Workshop, 248 (1994).Google Scholar
8. Jerman, H, “Electrically-activated, micromachined diaphragm valves,” Proc. IEEE Solid State Sensors and Actuators Workshop, 65 (1990).Google Scholar
9. Nakagawa, S., Shoji, S., and Esashi, M., “A microchemical analyzing system integrated on a silicon wafer,” Proc. IEEE Solid State Sensors and Actuators Workshop, 89 (1990).Google Scholar
10. Smith, R.L. Bower, R.W., and Collins, S.D., “The design and fabrication of a magnetically actuated micromachined flow valve,” Sensors and Actuators A, 24, 47 (1990).Google Scholar
11. Zdeblick, M.J., Anderson, R., Jankowski, J., Kline-Schoder, B., Christel, L., Miles, R., and Weber, W., “Thermpneumatically actuated microvalves and integrated electro-fluidic circuits,” Proc. IEEE Solid State Sensors and Actuators Workshop, 251 (1994).Google Scholar
12. Ray, C.A., Sloan, C.L., Johnson, A.D., Busch, J.D., and Petty, B.R., “A silicon-based shape memory alloy microvalve,” in Smart Materials Fabrication and Materials for Micro-Electro-Mechanical Systems, ed. by Jardine, A.P., Johnson, G.C., Crowson, A., and Allen, M. (Mater. Res. Soc. Proc. 276, Pittsburgh, PA 1992), 161.Google Scholar
13. Wolf, R.H. and Heuer, A.H., “TiNi (shape memory) films on silicon for MEMS applications,” J. Microelectromechanical Systems, 4, 206 (1995).Google Scholar
14. Allen, M.G., Mehregany, M., Howe, R.T., and Senturia, S.D., “Microfabricated structures for the in situ measurement of residual stress, Young's modulus, and ultimate strain of thin films,” Appl. Phys. Lett., 51, 241 (July 1987).Google Scholar
15. Ikata, K. and Shimizu, H., “Two dimensional mathematical model of shape memory alloys and intelligent SMA-CAD,” Proc. IEEE Micro-electro-mechanical Systems Workshop, 87 (1993).Google Scholar