Hostname: page-component-78c5997874-m6dg7 Total loading time: 0 Render date: 2024-11-03T05:13:23.920Z Has data issue: false hasContentIssue false

Chemical Vapor Deposition of Electroceramic Thin Films

Published online by Cambridge University Press:  29 November 2013

Get access

Extract

A nonconventional way of producing nonvolatile memories is to use ferroelectrics, a class of electroceramic materials. These materials have a remanent polarization. The direction of this polarization can be changed by an electric field. Ferroelectric materials possess a “natural memory,” so to speak. Ferroelectrics have been known for a long time, and the idea to use them for binary data storage originates in the 1950s. The basic element of this type of memory is formed by a ferroelectric capacitor—a ferroelectric layer sandwiched between electrodes. Early prototypes were unsuccessful because rather high voltages were needed to switch the ferroelectric capacitor (200–300 V) and the memories suffered from crosstalk. (Programming one particular cell influenced neighboring cells.) The revival of ferroelectric memories was driven by the development of thin-film deposition techniques that allowed the formation of capacitors with ferroelectric thin films of submicron thicknesses. These capacitors can be switched with normal intergrated-circuit (IC) voltages. The crosstalk problem is circumvented by isolating each memory cell by a transistor (similar to a dynamic random-access memory [DRAM]). Compared to “standard” nonvolatile memories, ferroelectric memories offer the advantage of very fast access times (both for reading and writing), low-voltage operation, and good write/read endurance. A ferroelectric material that is already being used in commercially available memories is lead zirconate titanate, PbZrxTi 1−xO3. To combine a ferroelectric material with IC technology is a challenge, and many problems have been (and will be) encountered.

Type
Electroceramic Thin Films Part I: Processing
Copyright
Copyright © Materials Research Society 1996

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. See for example, Green, M.L., Gross, M.E., Papa, L.E., Schnoes, K.J., and Brasen, D., J. Electrochem. Soc. 132 (1985) p. 2677.CrossRefGoogle Scholar
2. See for example, Wills, L.A., Feil, W.A., Wessels, B.W., Tonge, L.M., and Marks, T.J., J. Cryst. Growth 107 (1991) p. 712.CrossRefGoogle Scholar
3. For high-Tc superconductors, see for example, High Temperature Superconductors: Fundamental Properties and Novel Materials Processing, edited by Christen, D., Narayan, J., and Schneemeyer, L. (Mater. Res. Soc. Symp. Proc. 169, Pittsburgh, 1990).Google Scholar
4. For (Ba,Sr)TiO3, see for example, Kawahara, T., Yamamuka, M., Makita, T., Naka, J., Yuuki, A., Mikami, N., and Ono, K., Jpn. J. Appl. Phys. 33 (1994) p. 5129.CrossRefGoogle Scholar
5. For MgA12O4, see for example, Zhang, J., Stauf, G.T., Gardiner, R., Van Buskirk, P., and Steinbeck, J., J. Mater. Res. 9 (1994) p. 1333.CrossRefGoogle Scholar
6.Kirlin, P., Bilodeau, S., and Buskirk, P. Van, Integrated Ferroelectrics 7 (1995) p. 307.CrossRefGoogle Scholar
7.Hiskes, R., DiCarolis, S.A., Jacowitz, R.D., Lu, Z., Feigelson, R.S., Route, R.K., and Young, J.L., J. Cryst. Growth 128 (1993) p. 781.CrossRefGoogle Scholar
8.Okada, M. and Tomita, K., U.S. Patent No. 4,792,463 (1988).Google Scholar
9.Vossen, J.L. and Kern, W., eds., Thin Film Processes (Academic Press, New York, 1978).Google Scholar
10.McMillan, L.D., Roberts, T.L., Scott, M.C., and de Araujo, C.A. Paz, in Proc. 4th Int. Symp. Integrated Ferroelectrics (Monterey, 1992) p. 666.Google Scholar
11.de Keijser, M., van Veldhoven, P.J., and Dormans, G.J.M., in Ferroelectric Thin Films III, edited by Myers, E.R., Tuttle, B.A., Desu, S.B., and Larsen, P.K. (Mater. Res. Soc. Symp. Proc. 310, Pittsburgh, 1993) p. 223.Google Scholar
12.Dormans, G.J.M., van Veldhoven, P.J., and de Keijser, M., J. Cryst. Growth 123 (1992) p. 537.CrossRefGoogle Scholar