Interfacial Electronic Structure of Thin Cu Films Grown on Ar+-ion Sputter-cleaned a-Al2O3 Substrates

Abstract

Abstract: The bonding and electronic structure of Cu/(0001)Al2O3 and Cu/(1120)Al2O3 interfaces has been studied experimentally using spatially-resolved transmission electron energy loss spectroscopy. The specimen were prepared by depositing Cu on single-crystal a-Al2O3 substrates, which have been Ar+-ion sputter-cleaned prior to the growth of Cu. For both orientations of the a-Al2O3 substrate, atomically abrupt interfaces formed as determined by high-resolution transmission electron microscopy. The investigations of the interfacial Cu-L2,3, Al-L2,3 and O-K energy loss near-edge structures, which are proportional to the site- and angular-momentum-projected unoccupied density of states above the Fermi level, indicate the existence of metallic Cu-Al bonds at the Cu/Al2O3 interface independent of the substrate orientation.

Key words: Electronic structure, Cu film, Ion sputtering, a-Al2O3

Christina Scheu, Min Gao, Manfred Rühle. Interfacial Electronic Structure of Thin Cu Films Grown on Ar+-ion Sputter-cleaned a-Al2O3 Substrates[J]. J Mater Sci Technol, 2002, 18(02): 117-120.

References

[1] M.M.Disko, C.C.Ahn and B.Fultz: Applications of Transmission Electron Energy-Loss Spectroscopy in Materials Science, Pennsylvania, Warrendale, The Minerals, Metals & Materials Society, 1992.
[2] R.F.Egerton: Electron Energy Loss Spectroscopy in the Electron Microscope, 2nd. edn., New York, Plenum Press, 1996.
[3] D.K.Saldin and J.M.Yao: Phys. Rev. B, 1990, 41(1), 52.
[4] R.Brydson: EMSA Bulletin, 1991, 21:2, 57.
[5] P.Rez, J.Bruley, P.Brohan, M.Payne and L.A.J.Garvie: Ultra-microscopy, 1995, 59, 159.
[6] N.D.Browning, M.F.Chisholm and S.J.Pennycook: Nature, 1993, 366, 143.
[7] J.Bruley, R.Brydson, H.Müllejans, J.Mayer, G.Gutekunst, W.Mader, D.Knauss and M. Rühle: J. Mater. Res., 1994, 9(10), 2574.
[8] R.Brydson, H. Müllejans, J.Bruley, P.Trusty, X.Sun, J.Yeomans and M. Rühle: J. Microscopy, 1995, 177, 369.
[9] C.Scheu, G.Dehm, M.Rühle and R.Brydson: Phil. Mag. A,
1998,78(2), 439.
[10] D.A.Muller, D.J.Singh and J.Silcox: Phys.Rev.B, 1998, 57,
8181.
[11] D.A.Muller, D.A.Shashkov, R.Benedek, L.H.Yang and J.Silcox:
Phys. Rev. Lett., 1998, 80, 4741.
[12] D.Imhoff, S.Laurent, C.Colliex and M.Backhaus-Ricoult: Eur.
Phys. J. AP, 1999, 5, 9.
[13] S.Nufer, A.G.Marinopoulos, T.Gemming,
C.Els(?)sser,W.Kurtz,S.K(?)stlmeier and M.Rühle: Eur.Phys.J. AP,
1999,5, 9.
[14] J.Bruley, V.J.Keast and D.B.Williams: J. Phys. D: Appl. Phys., 1996, 29, 1730.
[15] G.Duscher, N.D.Browning and S.J.Pennycook: Phys. Stat. Sol. A, 1998, 166, 327.
[16] D.A.Muller, D.J.Singh and J.Silcox: Phys. Rev. B, 1998, 57, 8181.
[17] A.Strecker and U.Salzberger: J. Mayer, Prakt. Metallogr., 1993, 30, 482.
[18] J.Bruley: Microsc. Microanal. Microstruct., 1993, 4, 23.
[19] H.Müllejans and J.Bruley: J. Microscopy, 1995, 180, 12.
[20] C.Scheu, G.Dehm, H.Mllejans, R.Brydson and
M.Rühle: Microsc. Microanal. Microstruct., 1995, 6, 19.
[21] H.Gu, M.Ceh, S.Stemmer, H.Müllejans and M.Ruhle: Ultra-microscopy, 1995, 59, 215.
[22] C.Scheu, W.Stein and M.Rühle: Phys. Stat. Sol. (b), 2000, 222, 199.
[23] D.A.Smith, D.T.Carpenter, S.J.Splinter and J.T.Bruley: Interface Science and Materials Interconnection, Proceedings of JIMIS-8, The Japan Institute of Metals, 1996, 21.
[24] R.Brydson: J. Phys. D: Appl. Phys., 1996, 29.
[25] J.Ahn and J.W.Rabalais: Surface Science, 1997, 388, 121.
[26] K.C.Hass, W.F.Schneider, A.C.Curioni and W.Andreoni: Science, 1998, 282, 265.
[27] P.J.Eng, T.P.Trainor, G.E.Brown, G.A.Waychunas, M.Newville, S.R.Sutton and M.L.Rivers: Science, 2000, 288, 1029.
[28] J.A.Kleber, C.Niu, K.Shepherd, D.R.Jennison and A.Bogicevic: Surface Science, 2000, 446, 76.@