Abstract
The stability of interfaces with germanium, which has recently been discussed as a replacement for silicon in ultra-large-scale integrated circuits (ULSIs), was studied. Interfacial oxygen diffusion from high-permittivity gate dielectrics (ZrO2 and HfO2) into germanium substrates must be suppressed to prevent the formation of interfacial layers between the gate dielectrics and the germanium substrates. Oxygen diffusion was simulated through a molecular-dynamics technique that takes into account many-body interactions and charge transfer between different elements. The simulation results show that the addition of yttrium is effective in suppressing interfacial oxygen diffusion at the ZrO2/germanium interfaces. On the other hand, the addition of yttrium is not effective in suppressing interfacial oxygen diffusion at the HfO2/germanium interfaces. The results also show that the diffusion at the ZrO2/Ge(111) and HfO2/Ge(111) interfaces is much more suppressed than the diffusion at the ZrO2/Ge(001) and HfO2/Ge(001) interfaces.
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D. Chi, C.O. Chui, K.C. Sawaswat, B.B. Triplett, and P.C. Mclntyre: Zirconia grown by ultraviolet ozone oxidation on germanium (100) substrates. J. Appl. Phys. 96, 813 (2004).
H. Kim, C.O. Chui, K.C. Sawaswat, and P.C. Mclntyre: Local epitaxial growth of ZrO2 on Ge (100) substrates by atomic layer epitaxy. Appl. Phys. Lett. 83, 2647 (2003).
C.O. Chui, H. Kim, D. Chi, B.B. Triplett, P.C. Mclntyre, and K.C. Sawaswat: A sub-400°C germanium MOSFET technology with high-k dielectric and metal gate, in 2003 IEEE International Electronics Devices Meeting, edited by L. Lunardi (Washington, DC, 2002) p. 437.
H. Ota, S. Migita, Y. Morita, and S. Sakai: HfO2 MIS structures with a silicon nitride barrier layer. Extended Abstracts of International Workshop on Gate Insulator 2001, 188 (2001).
K-J. Choi, W-C. Shin, and S-G. Yoon: Ultrathin HfO2 gate dielectric grown by plasma-enhanced chemical vapor deposition using Hf[OC(CH3)3]4 as a precursor in the absence of O2. J. Mater. Res. 18, 60 (2003).
R.M. Wallace, and G. Wilk: Alternative gate dielectrics for microelectronics. MRS Bull. 27(3), 186 (2002).
A.I. Kingon, J-P. Maria, D. Wicaksana, and C. Hoffman: Compatibility of candidate high permittivity gate oxides with front and backend processing conditions. Extended Abstracts of International Workshop on Gate Insulator 2001, 36 (2001).
Y. Morisaki, Y. Sugita, K. Irino, and T. Aoyama: Effects of interface oxide layer on HfO2 gate dielectrics. Extended Abstracts of International Workshop on Gate Insulator 2001, 184 (2001).
S.J. Lee, C.H. Lee, Y.H. Kim, H.F. Luan, W.P. Bai, T.S. Jeon, and D.L. Kwong: Dual-poly CVD HfO2 gate stack for sub-100 nm CMOS technology. Extended Abstracts of International Workshop on Gate Insulator 2001, 80 (2001).
M. Sohgawa, S. Kitai, H. Kanda, T. Kanashima, A. Fujimoto, and M. Okuyama: Preparation and characterization of ZrO2/Si structure. Extended Abstracts of International Workshop on Gate Insulator 2001, 170 (2001).
T. Iwasaki: Molecular-dynamics analysis of interfacial diffusion between high-permittivity gate dielectrics and silicon substrates. J. Mater. Res. 19, 1197 (2004).
A. Yasukawa: Using an extended Tersoff interatomic potential to analyze the static-fatigue strength of SiO2 under atmospheric influence. JSME Int. J. Ser. A 39, 313 (1996).
S.J. Wang and C.K. Ong: Epitaxial Y-stabilized ZrO films on silicon: Dynamic growth process and interface structure. Appl. Phys. Lett. 80, 2541 (2002).
W. Heermann: Computer Simulation Methods, 2nd ed. (Springer-Verlag, Berlin, Germany, 1989), p. 13.
L.V. Woodcock: Isothermal molecular dynamics calculations for liquid salts. Chem. Phys. Lett. 10, 257 (1971).
T. Iwasaki: Molecular dynamics study of diffusion and atomic configuration in layered structures for Al circuit interconnects. Comput. Mech. 24, 148 (1999).
T. Iwasaki: Molecular dynamics study of adhesion strength and diffusion at interfaces between interconnect materials and underlay materials. Comput. Mech. 25, 78 (2000).
T. Iwasaki, and H. Miura: Molecular dynamics analysis of adhesion strength of interfaces between thin films. J. Mater. Res. 16, 1789 (2001).
J. Tersoff: Modeling solid-state chemistry: Interatomic potentials for multicomponent systems. Phys. Rev. B39, 5566 (1989).
F. Ercolessi and J.B. Adams: Interatomic potentials from firstprinciples calculations: The force-matching method. Europhys. Lett. 26, 583 (1994).
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Iwasaki, T. Molecular-dynamics study of interfacial diffusion between high-permittivity gate dielectrics and germanium substrates. Journal of Materials Research 20, 1300–1307 (2005). https://doi.org/10.1557/JMR.2005.0158
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DOI: https://doi.org/10.1557/JMR.2005.0158