Hostname: page-component-586b7cd67f-tf8b9 Total loading time: 0 Render date: 2024-11-27T00:40:40.086Z Has data issue: false hasContentIssue false

Relationships Between Microstructure and Reliability in Pzt Mems

Published online by Cambridge University Press:  21 March 2011

B.W. Olson
Affiliation:
Mechanical and Materials Engineering, Washington State University, Pullman WA 99164-2920
L.M. Randall
Affiliation:
Mechanical and Materials Engineering, Washington State University, Pullman WA 99164-2920
C.D. Richards
Affiliation:
Mechanical and Materials Engineering, Washington State University, Pullman WA 99164-2920
R.F. Richards
Affiliation:
Mechanical and Materials Engineering, Washington State University, Pullman WA 99164-2920
D.F. Bahr
Affiliation:
Mechanical and Materials Engineering, Washington State University, Pullman WA 99164-2920
Get access

Abstract

Piezoelectric oxide films, such as lead zirconate titanate (PZT), are now being integrated into MEMS applications. Many PZT derived systems are deposited using a sol-gel process, which can be used in a microelectronics processing route using spin coating as the deposition method. An application of interest for PZT films is in power generation, where a flexing membrane is used to transform mechanical to electrical energy. The current study was undertaken to identify the relationships between the processing, microstructure, and mechanical reliability of these films. Films were deposited onto both monolithic and bulk micromachined platinized silicon wafers using standard sol-gel chemistries, with roughness and grain size tracked using electron and scanning probe microscopy. Mechanical properties were evaluated in a dynamic bulge testing apparatus. Grain size variations in the Pt film between 35 and 125 nm are shown to have little effect on grain size of the subsequent PZT film and the adhesion of the PZT to the Pt film. Only the Pt film with 125 nm grains was shown to undergo any significant interfacial fracture. Fatigue tests suggest film lifetime is primarily limited by the number of pre- existing flaws in the film from processing. Reducing the microcrack density has been shown to produce films and devices that fail at strains of 1.4% and have mechanical fatigue lifetimes in excess of 100 million cycles at strains simulating the operating conditions.

Type
Research Article
Copyright
Copyright © Materials Research Society 2001

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

REFERENCES

1. Bahr, D.F., Crozier, B.T., Richards, C.D., and Richards, R.F., Mater. Res. Soc. Symp. Proc., Materials Science of MEMS Devices III (2001) (in press).Google Scholar
2. Chen, S. and Chen, I., J. Am. Ceram. Soc. 81, 97 (1998).Google Scholar
3. Floquet, N., Hector, J. and Gaucher, P., J. Appl. Phys. 84, 3815 (1998).Google Scholar
4. Kanai, H., Yamashita, Y., and Yamakawa, K., 11 th IEEE Int. Symp. On Appl. Of Ferroe. Proc., 121 (1998).Google Scholar
5. Kim, J., Khamankar, R., Jiang, B., Maniar, P., Moazzami, R., Jones, R.E., and Lee, J.C., Mater. Res. Soc. Symp. Proc., Ferroelectric Thin Films IV 361, 409 (1995).Google Scholar
6. Fu, X., Li, J., Song, Z., and Lin, C., J. of Crystal Growth 220, 86 (2000).Google Scholar
7. Ea-Kim, B., Varniere, F., Hugon, M.C., Agius, B., Bisaro, R., and Olivier, J., Mater. Res. Soc. Symp. Proc., Ferroelectric Thin Films V 433, 163 (1996).Google Scholar
8. Li, T., Hsu, S.T., Gao, Y., and Engelhard, M., Mater. Res. Soc. Symp. Proc., Ferroelectric Thin Films VIII 596, 199 (2000).Google Scholar
9. Fujisawa, H., Nakashima, S., Shimizu, M., and Niu, H., Mater. Res. Soc. Symp. Proc., Ferroelectric Thin Films VII 541, 327 (1999).Google Scholar
10. Lee, W.I., and Lee, J.K., Mat. Res. Bull. 30, 1188 (1995).Google Scholar
11. Jin, B.M, Kim, J., and Kim, S.C., Appl. Phys. A. 65, 53 (1997).Google Scholar
12. Wang, Z., Maeda, R., and Kikuchi, K., Jpn. J. Appl. Phys. 38, 5342 (1999).Google Scholar
13. Kakegawa, K., Matsunaga, O., Kato, T., and Sasaki, Y., J. Am. Ceram. Soc. 78, 1071 (1995).Google Scholar
14. Tuttle, B.A., Headley, T.J., Al-Shareef, H.N., Voigt, J.A., Rodriguez, M., and Michail, J., J. Mater. Res. 11, 2309 (1996).Google Scholar
15. Ahn, C. H., Tybell, T., Kuffer, O., Antognazza, L., Char, K., Hammond, R.H., Beasley, M.R., Fischer, O., and Triscone, J.M., Mat. Sci. and Eng. B56, 173 (1998).Google Scholar
16. Kneer, E.A., Birnie, D.P. III, Teowee, G., and Pdolesny, J.C., Ferro. Proc. Of the 8 th Int. Meeting on Ferroelectrics. 152, 67 (1994).Google Scholar
17. Lian, L., and Sottos, N.R., J. of Appl. Phys. 87, 3948 ( 2000).Google Scholar
18. Al-Shareef, H.N., Kingon, A.I., Chen, X., and Gellur, K.R., J. Mater. Res., 9, 2968 (1994).Google Scholar
19. Nam, H., Choi, D., and Lee, W., Thin Solid Films 371, 264 (2000).Google Scholar
20. Lee, J., Park, E., Park, J., Lee, B., and Joo, S., Mater. Res. Soc. Symp. Proc., Ferroelectric Thin Films VIII 596, 315 (2000).Google Scholar
21. Budd, K.D., Dey, S.K., and Payne, D.A., British Ceramic Proceedings Electrical Ceramics 36, 107 (1985).Google Scholar
22. Bahr, D.F., Crozier, B.T., Richards, C.D., and Richards, R.F., in Mechanical Properties of Structural Films, STP No. 1413, Muhlstein, C.L. and Brown, S.B., Eds., ASTM, West Conshohocken, PA, in press (2001).Google Scholar