| AVS 54th International Symposium | |
| Thin Film | Thursday Sessions |
| Session TF-ThM |
| Session: | Thin Films for Electronic Applications |
| Presenter: | T.S. Lazarz, University of Illinois at Urbana-Champaign |
| Authors: | T.S. Lazarz, University of Illinois at Urbana-Champaign Y. Yang, University of Illinois at Urbana-Champaign N. Kumar, University of Illinois at Urbana-Champaign W. Noh, University of Illinois at Urbana-Champaign G.S. Girolami, University of Illinois at Urbana-Champaign J.R. Abelson, University of Illinois at Urbana-Champaign |
| Correspondent: | Click to Email |
Ruthenium is being investigated for multiple uses in microelectronics, including DRAM capacitors,1 metal gates in p-MOSFETs,2 and in the copper dual damascene process.3 Previous studies have generally prepared Ru films by evaporation or by CVD from ruthenocene or its ring-substituted analogues. Other ruthenium compounds such as β-diketonates, arenes, dienes and carbonyls have also been investigated as CVD precursors. In all cases, however, the growth rates been unsatisfactory (< 2 nm/min), the films have been contaminated by heteroatoms due to ligand incorporation, or there have been nucleation problems on covalent substrates.4 We have used the single-source liquid precursor tricarbonyl(1,3-cyclohexadiene)ruthenium(0), C6H8Ru(CO)3, to deposit metallic ruthenium films by CVD at substrate temperatures ranging between 150 and 600 °C on several types of substrates, including covalent. Ligand removal is expected to be relatively facile from this Ru(0) compound due to the ruthenium atom being in oxidation state zero on the precursor molecule. The Ru growth rates are rapid, with a maximum of 19 nm/min. The oxygen content is below AES detection limits (< 1 at. %), and the carbon content is estimated to be low. In-situ spectroscopic ellipsometry indicates negligibly short delays before film nucleation on Si, SiO2, or sapphire substrates. The resistivities are comparable to the bulk resistivity, ranging between 11 and 21 μΩ-cm. The texture of the films depends on deposition temperature. At lower temperatures, films are strongly textured mostly in the (0002) direction, whereas at higher temperatures the films are less textured. Since C6H8Ru(CO)3 gives high growth rates, low resistivities, and nucleates readily on all surfaces tested, C6H8Ru(CO)3 is an excellent precursor for depositing thin ruthenium films.
1 T. Aoyama and K. Eguchi, Japanese Journal of Applied Physics, Part 2 (Letters) 38 (10A), 1134 (1999).
2 V. Misra, G. Lucovsky, and G. Parsons, MRS Bulletin 27 (3), 212 (2002).
3 T.N. Arunagiri, Y Zhang, and O Chyan, Applied Physics Letters 86 (2005); Hoon Kim, Toshihiko Koseki, Takayuki Ohba et al., Journal of The Electrochemical Society 152 (8), G594 (2005).
4Sang Yeol Kang, Cheol Seong Hwang, and Hyeong Joon Kim, Journal of The Electrochemical Society 152 (1), C15 (2005).