Extending the scalability of deep trench capacitor dynamic random access memories requires introduction of a high-k dielectric-based storage capacitor structure. Pr-enriched Al2O3 dielectrics with TiN electrodes appear as a promising materials system for this application. Electrical measurements performed on this materials combination show, however, that achieving a very low capacitance equivalent thickness and low leakage current requires very careful control of the electrode/dielectric interface properties. In particular, formation of a parasitic interface layer has to be avoided. For this purpose, we carried out a systematic synchrotron radiation x-ray photoelectron spectroscopy study to non-destructively investigate the interface reactivity of the PrxAl2-xO3 (x = 0, 1, 2)dielectrics with TiN metal electrodes. The depth profiling study shows that the TiN substrate is covered with a native TiO2. Additionally, a thin interfacial Ti oxynitride layer is present between these compounds, resulting in a TiN/TiNO/TiO2 materials stack. Molecular beam deposition of Al2O3 onto substrates of this structure leads to a remarkable reduction of the native oxide. In contrast, in the same way deposited PrAlO3 and Pr2O3 dielectrics are significantly less reactive towards TiO2. As a consequence, the native TiON/TiO2 remains the main component of the interface layer in the TiN/PrAlO3 and TiN/Pr2O3 capacitor stacks. Such a configuration poses severe scalability problems to the Pr aluminate dielectrics.
This is a preview of subscription content, access via your institution.
Buy single article
Instant access to the full article PDF.
Tax calculation will be finalised during checkout.
W. Mueller, G. Aichmayr, W. Bergner, E. Erben, T. Hecht, C. Kapteyn, A. Kersch, S. Kudelka, F. Lau, J. Luetzen, A. Orth, J. Nuetzel, T. Schloesser, A. Scholz, U. Schroeder, A. Sieck, A. Spitzer, M. Strasser, S. Wege, and R. Weis, IEDM Techn. Digest (2005).
J. Amon, A. Kieslich, T. Schuster, J. Faul, J. Luetzen, C. Fan, C.-C. Huang, B. Fischer, G. Enders, S. Kudelka, U. Schroeder, K.-H. Kuesters, G. Lange, and J. Alsmeier, IEDM Techn. Digest (2004)
T. Schroeder, G. Lupina, R. Sohal, G. Lippert and Ch. Wenger, O. Seifarth, M. Tallarida, and D. Schmeisser, J. Appl. Phys. 101, 014103 (2007)
F. Esaka, K. Furuya, H. Shimida, M. Imamura, N. Matsubayashi, H. Sato, and T. Kikuchi, J. Vac. Sci. Technol. A 15, 2521 (1997)
P. Prieto, and R. E. Kirby, J. Vac. Sci. Technol. A 13, 2819 (1995)
Y. C. Kim, H. H. Park, J. S. Chun, and W. J. Lee, Thin Solid Films, 237, 57 (1994)
Thermophysical properties of Matter, in TPRC Data Series, Vol. 13, edited by Y. S. Touloukian, R. K. Kirby, R. E. Taylor, and T. Y. R. Lee (Plenum, New York, 1977)
J.-C. Dupin, D. Gonbeau, P. Viantier, and A. Levasseur, Phys. Chem. Chem. Phys. 2, 1319 (2000)
About this article
Cite this article
Lupina, G., Schroeder, T., Wenger, C. et al. Interface Properties of PrxAl2-xO3 (x = 0 to 2) Dielectrics on TiN Studied by Synchrotron Radiation X-ray Photoelectron Spectroscopy. MRS Online Proceedings Library 1000, 603 (2007). https://doi.org/10.1557/PROC-1000-L06-03