Optical metrology of Ni and NiSi thin films used in the self-aligned silicidation process

The thickness-dependent optical properties of nickel metal and nickel monosilicide (NiSi) thin films, used for self-aligned silicidation process, were characterized using spectroscopic ellipsometry. The thickness-dependent complex dielectric function of nickel metal films is shown to be correlated with the change in Drude free electron relaxation time. The change in relaxation time can be traced to the change in grain boundary (GB) reflection coefficient and grain size. A resistivity based model was used as the complementary method to the thickness-dependent optical model to trace the change in GB reflection coefficient and grain size. After silicidation, the complex dielectric function of NiSi films exhibit non-Drude behavior due to superimposition of interband absorptions arising at lower frequencies. The Optical models of the complete film stack were refined using x-ray photoelectron spectroscopy, Rutherford backscattered spectroscopy, and x-ray reflectivity (XRR).

[1]  A. Demkov,et al.  Electronic, optical, and surface properties of PtSi thin films , 2008 .

[2]  James N. Hilfiker,et al.  Survey of methods to characterize thin absorbing films with Spectroscopic Ellipsometry , 2008 .

[3]  W. Li,et al.  Synthesis of a nano-nickel catalyst modified by ruthenium for hydrogenation and hydrodechlorination , 2008 .

[4]  N. Barreau,et al.  Spectroscopic ellipsometry studies of In2S3 top window and Mo back contacts in chalcopyrite photovoltaics technology , 2008 .

[5]  A. Oliva,et al.  Surface and grain boundary contributions in the electrical resistivity of metallic nanofilms , 2006 .

[6]  S. Zhang.  Nickel-based contact metallization for SiGe MOSFETs: progress and challenges , 2003 .

[7]  Pooi See Lee,et al.  Phase and Layer Stability of Ni- and Ni(Pt)-Silicides on Narrow Poly-Si Lines , 2002 .

[8]  K. Omote,et al.  The genetic algorithm: refinement of X-ray reflectivity data from multilayers and thin films , 2000 .

[9]  Albert Frederick Carley,et al.  The formation and characterisation of Ni3+ — an X-ray photoelectron spectroscopic investigation of potassium-doped Ni(110)–O , 1999 .

[10]  R. Pretorius,et al.  A study of the NiSi to NiSi2 transition in the Ni-Si binary system , 1999 .

[11]  M. Hietschold,et al.  XTEM Studies of Nickel Silicide Growth on Si(100) Using a Ni/Ti Bilayer System , 1997 .

[12]  C. Mims,et al.  Synthesis and Characterization of LaCr1−xNixO3Perovskite Oxide Catalysts , 1997 .

[13]  Collins,et al.  Evolution of the optical functions of thin-film aluminum: A real-time spectroscopic ellipsometry study. , 1993, Physical review. B, Condensed matter.

[14]  H. Nguyen,et al.  In situ determination of dielectric functions and optical gap of ultrathin amorphous silicon by real time spectroscopic ellipsometry , 1991 .

[15]  George M. Whitesides,et al.  The structure of self-assembled monolayers of alkylsiloxanes on silicon: a comparison of results from ellipsometry and low-angle x-ray reflectivity , 1989 .

[16]  D. Aspnes,et al.  Unambiguous determination of thickness and dielectric function of thin films by spectroscopic ellipsometry , 1984 .

[17]  T. Barr.  An XPS study of Si as it occurs in adsorbents, catalysts, and thin films , 1983 .

[18]  N. Cheung,et al.  Metal-semiconductor interfacial reactions - Ni/Si system , 1981 .

[19]  F. Grunthaner,et al.  XPS study of the chemical structure of the nickel/silicon interface. [X-ray Photoelectron Spectroscopy , 1980 .

[20]  N. Winograd,et al.  X-Ray photoelectron spectroscopic studies of ruthenium-oxygen surfaces , 1974 .

[21]  F. Wooten,et al.  Optical Properties of Solids , 1973 .

[22]  N. Ashcroft,et al.  Interband Absorption and the Optical Properties of Polyvalent Metals , 1971 .

[23]  M. Shatzkes,et al.  Electrical-Resistivity Model for Polycrystalline Films: the Case of Arbitrary Reflection at External Surfaces , 1970 .

[24]  M. Shatzkes,et al.  ELECTRICAL RESISTIVITY MODEL FOR POLYCRYSTALLINE FILMS: THE CASE OF SPECULAR REFLECTION AT EXTERNAL SURFACES , 1969 .

[25]  H. Ehrenreich,et al.  Optical Properties and Fermi Surface of Nickel , 1963 .

[26]  Zexiang Shen,et al.  Thermal stability study of NiSi and NiSi 2 thin films , 2004 .

[27]  P. Sherwood,et al.  Dissolution and passivation of nickel. An X-ray photoelectron spectroscopic study , 1977 .

[28]  F. Wooten.  Chapter 3 – ABSORPTION AND DISPERSION , 1972 .

[29]  C. Nordling,et al.  Band Structure of Transition Metals Studied by ESCA , 1970 .

[30]  L. Alexander,et al.  X-ray diffraction procedures , 1954 .