Hostname: page-component-5c6d5d7d68-7tdvq Total loading time: 0 Render date: 2024-08-19T03:42:04.002Z Has data issue: false hasContentIssue false
  • English
  • Français

Etching of Zirconium Oxide, Hafnium Oxide, and Hafnium Silicates in Dilute Hydrofluoric Acid Solutions

Published online by Cambridge University Press:  03 March 2011

Viral Lowalekar  and
Srini Raghavan
Viral Lowalekar
Affiliation:
Department of Materials Science and Engineering, The University of Arizona, Tucson, Arizona 85721
Srini Raghavan
Affiliation:
Department of Materials Science and Engineering, The University of Arizona, Tucson, Arizona 85721
Get access

Abstract

Oxides and silicates of zirconium and hafnium are actively being considered and tested to replace SiO2 as the gate material. Though these materials have the high-dielectric constant (k ∼ 20–25) needed to provide a larger equivalent oxide thickness, they are very refractory and difficult to etch by wet and dry methods. In this paper, work done on wet etching of ZrO2, HfO2, and HfSixOy in dilute hydrofluoric acid (HF) solutions is presented and discussed. Experiments were done on various high-k films deposited by metalorganic chemical vapor deposition. It was found that the as-deposited high-k films can be dissolved with a good selectivity over SiO2 in dilute HF solutions, but heat-treated high-k films are difficult to etch with good selectivity over SiO2 under the same conditions.

Keywords

Chemical reactionDieletric
Type
Articles
Information
Journal of Materials Research , Volume 19 , Issue 4 , April 2004 , pp. 1149 - 1156
Copyright
Copyright © Materials Research Society 2004

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 The International Technology Roadmap for Semiconductors (2001)Google Scholar
2Degraeve, R., Kaczer, B., Groeseneken, G. and Reliability: A possible showstopper for oxide thickness scaling? Semicon. Sci. Technol. 15, 436 (2000).CrossRefGoogle Scholar
3Nieh, R., Onishi, K., Choi, R., Dharmarajan, E., Goplan, S., Kang, C.S., and Lee, J.C.: High-K gate dielectrics: HfO2, ZrO2 and their silicates, Proceedings Electrochemical Society, 2001-9 (Rapid Thermal and Other Short-Time Processing Technologies II), 171 (2001).Google Scholar
4Wilk, G.D., Wallace, R.M. and Anthony, J.M.: Hafnium and zirconium silicates for advanced gate dielectrics. J. Appl. Phys. 87, 484 (2000).CrossRefGoogle Scholar
5Wilk, G.D., Wallace, R.M. and Anthony, J.M.: High-k gate dielectrics: Current status and materials properties considerations. J. Appl. Phys. 89, 5243 (2001).CrossRefGoogle Scholar
6Wilk, G.D. and Wallace, R.M.: Electrical properties of hafnium silicate gate dielectrics deposited directly on silicon. Appl. Phys. Lett. 74, 2854 (1999).CrossRefGoogle Scholar
7Wilk, G.D. and Wallace, R.M.: Stable zirconium silicate gate dielectrics deposited directly on silicon. Appl. Phys. Lett. 76, 112 (2000).CrossRefGoogle Scholar
8Vandervorst, W., Brijs, B., Bender, H., Conard, O.T., Petry, J., Richard, O., Van Elshocht, S., Delabie, A., Caymax, M. and De Gendt, S. Physical characterization of ultrathin high k dielectrics, in Novel Materials and Processes for Advanced CMOS, edited by Gardner, M.I., De Gendt, S., Maria, J-P., and Stemmer, S., (Mater. Res. Soc. Symp. Proc. 745, Warrendale, PA, 2003) p. 230Google Scholar
9Watanabe, D., Momota, H., Kezuka, T., Takashi, K., Mitsushi, I., Riley, D., and Barnett, J., Selective wet etching for high-k material by organic solvent containing hydrofluoric acid, Semiconductor Pure Water and Chemicals Conference Proceedings, 22nd, 117, (2003).Google Scholar
10Guan, J.J., Gale, G.W., Bersuker, G., Jackson, M., and Huff, H.R.: Chemical processing and material compatibility of high-k dielectric materials for advanced gate stacks, Diffusion and Defect Data-Solid State Data, Pt. B: Solid State Phenomena, 76-77 (Ultra Clean Processing of Silicon Surfaces 2000), 19, (2000).Google Scholar
11Agarwal, A., Freiler, M., Lysaght, P., Perrymore, L., Bergmann, R., Sparks, C., Bowers, B., Barnett, J., Riley, D., Kim, Y., Nguyen, B., Bersuker, G., Shero, E., Lim, J.E., Lin, S., Chen, J., Murto, R.W. and Huff, H.R. Challenges in integrating the high-k gate dielectric film to the conventional CMOS process flow, in Gate Stack and Silicide Issues in Silicon Processing II, edited by Campbell, S.A., Clevenger, L.A., Griffin, P.B., and Hobbs, C.C., (Mater. Res. Soc. Symp. Proc., 670,Warrendale, PA, 2002) p. K2.1.1Google Scholar
12Saenger, K.L., Okorn-Schmidt, H.F. and D’Emic, C.P. A selective etching process for chemically inert high-k metal oxides, in Novel Materials and Processes for Advanced CMOS , edited by Gardner, M.I., De Gendt, S., Maria, J-P., and Stememr, S., (Mater. Res. Soc. Symp. Proc. 745, Warrendale, PA, 2003), p. 29Google Scholar
13Quevedo-Lopez, M.A., El-Bouanani, M., Wallace, R.M. and Gnade, B.E.: Wet chemical etching studies of Zr and Hf-silicate gate dielectrics. J. Vac. Sci. Technol. A. 20, 1891 (2002).CrossRefGoogle Scholar
14Christenson, K., Schwab, B., Wagener, T., Rosengren, B., Riley, D., and Barnett, J.: Selective wet etching of high-k gate dielectrics, Diffusion and Defect Data—Solid State Data, Pt. B: Solid State Phenomena, 92 (Ultra Clean Processing of Silicon Surfaces V), 129 (2003)CrossRefGoogle Scholar
15Barnett, J., Riley, D., Messina, T.C., Lysaght, P., and Carpio, R.: Wet etch enhancement of HfO2 films by implant processing, Diffusion and Defect Data—Solid State Data, Pt. B: Solid State Phenomena, 92 (Ultra Clean Processing of Silicon Surfaces V), 11 (2003).Google Scholar
16Huang, Hsin-Hsiung: STABCAL software, Metallurgical Engineering, Montana Tech., Butte, MT 59701, USAGoogle Scholar
17Knotter, D.M.: Etching mechanism of vitreous silicon dioxide in HF-based solutions. J. Am. Chem. Soc. 122, 4345 (2000).CrossRefGoogle Scholar
18Janusz, W.: Surface charge and adsorption of Na+ and Cl ions at the zirconium dioxide water interface. J. Radioanal. Nucl. Chem. 125, 393 (1988).CrossRefGoogle Scholar