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Dry Etching Issues in the Integration of Ferroelectric Thin Film Capacitors

Published online by Cambridge University Press:  10 February 2011

G. E. Menk ,
S. B. Desu ,
W. Pan  and
D. P. Vijay
G. E. Menk
Affiliation:
Department of Materials Science and Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
S. B. Desu
Affiliation:
Department of Materials Science and Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
W. Pan
Affiliation:
Department of Materials Science and Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
D. P. Vijay
Affiliation:
Department of Materials Science and Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
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Abstract

Dry etching is an area that demands a great deal of attention in the large scale integration of ferroelectric thin film capacitors for nonvolatile random access memory applications. In this review, we discuss some of the issues relating to the etching of the ferroelectric films, patterning of the electrodes, device damage caused by the etch process and post-etch residue problems. An etch process that can provide high etch rates and good etch anisotropy for the current candidate ferroelectrics including Pb(Zr, Ti)O3 and layered structure SrBi2Ta2O9 thin films using environmentally benign gases such as hydrochlorofluorocarbons is presented. The etch mechanism for both of these materials was determined to rely substantially on ion bombardment effects. For example, PZT films were etched anisotropically at rates of up to 60 nm/min using CHCIFCF3 gas under high rf power and low gas pressure conditions. Problems remain with respect to the acrosswafer differential etch rates observed when more than one phase is present in the material (e.g., amorphous/pyrochlore + perovskite phases in PZT). Damage caused by the etch process which can lead to changes in device characteristics, including hysteresis and fatigue properties, and the underlying mechanism that causes the damage are discussed. O2 was found to be a suitable etch gas for etching the conductive oxide electrode material RuO2. However, an anomaly in the etch rate was detected upon introduction of a small amount of fluorine containing gas: addition of 2% of CF3CFH2 gas to the O2 plasma increases the etch rate by a factor of four. This can be taken advantage of in obtaining high etch selectivity between the electrode and ferroelectric layers.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 433: Symposium T – Ferroelectric Thin Films V , 1996 , 189
Copyright
Copyright © Materials Research Society 1996

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References

1. Oehrlein, G.S. and Remletski, J.F., IBM J. Res. Develop., 36(2), 140, (1992).Google Scholar
2. Steinbruchel, C., Mat. Sci. and Technol., 8, 565, (1992).Google Scholar
3. Rossangel, S.M., Cuomo, J.J. and Westwood, W.D., Handbook of Plasma Processing Technology, Noyes Publications, Park Ridge, NJ, (1990).Google Scholar
4. Mocella, M.T., Solid State Technol, April 1991, 64, (1991).Google Scholar
5. Pan, W., Desu, S.B., Yoo, I. X and Vijay, D.P., J. Mater. Res., 9(11), 1994, 2976.Google Scholar
6. Vijay, D.P., Desu, S.B. and Pan, W., J.Electrochem. Soc., 140(9), 2635, (1993).Google Scholar
7. Lee, S., Esener, S., Tittle, M. and Drakik, T., Optical Engineering, 25, 250, (1986).Google Scholar
8. Poor, M.R., Hurd, A.M., Fleddeman, C.B. and Wu, A.Y., Mat. Res. Soc. Symp. Proc., 200, 211, (1990).Google Scholar
9. Saito, K, Choi, J.H., Fukuda, T. and Ohue, M., Jpn. J. Appl. Phys., 31, L1260, (1992).Google Scholar
10. Kwok, C. K and Desu, S.B., J. Mater. Res., 9(7), 1728, (1994).Google Scholar
11. Araujo, C.A. Paz de, Cuchlaro, J.D., McMillan, L.D. and Scott, M.C., Nature, 374, 627, (1995).Google Scholar
12. Desu, S.B. and Vijay, D.P., Mat. Sci. Engg., B32, 75, (1995).Google Scholar
13. Ammanuma, K, Hase, T. and Miyasaki, Y., Appl. Phys. Lett., 66(2), 221, (1995).Google Scholar
14. Desu, S.B. and Pan, W., Appl. Phys. Lett., 68(4), 566, (1996).Google Scholar
15. Langes Handbook of Chemistry, 13th Edition, McGraw-Hill, NY, (1994).Google Scholar
16. Vijay, D.P. and Desu, S.B., J. Electrochem. Soc., 140(9), 2640, (1993).Google Scholar
17. Dat, R., Lichenwalner, D.J., Auciello, O. and Kingon, A.I., Appl. Phys. Lett., 62(20), 2673, (1994).Google Scholar
18. Ramesh, R., Gilchrist, H., Sands, T., Keramidas, V.G., Haakenaasen, R-, and Fork, D. K, Appl. Phys. Lett., 61, 1537, (1992).Google Scholar
19. Bell, W.E. and Tagami, M., J. Phys. Chem., 67, 2433, (1963).Google Scholar
20. Pan, W. and Desu, S.B., J. Vac. Sci. Technol. B, 12(6), 3208, (1994).Google Scholar
21. Ramesh, R., Lee, J., Sands, T., Kermidas, V.G., Appl. Phys. Lett., 64, 2511, (1994).Google Scholar
22. Dhote, A.M., Madhukar, S., tei, W., Venkatesan, T., Ramesh, R. and Cotell, C.M., Appl. Phys. Lett., 68(10), 1350, (1996).Google Scholar
23. Pang, S.W., Solid State Technol., 27, 249, (1984).Google Scholar
24. Flamm, D.L., Cowan, P.L. and Golovchenko, J.A., J. Vac. Sci. Technol., 17, 1341, (1980).Google Scholar
25. Deepe, H. P., Hasler, B. and Hopfnler, J., Solid State Electronics, 20, 51, (1977).Google Scholar