Study of sputtered molybdenum nitride as a diffusion barrier

Abstract Molybdenum nitride thin films were deposited using reactive r.f. magnetron sputtering. Single phase γ-Mo 2 N films having f.c.c. structure and exhibiting metallic conductivity have been obtained over a wide range of nitrogen partial pressures. The temperature dependence of resistivity studied in the range 30–300 K showed a negative temperature coefficient of resistivity for all the films. The activation energy was found to be temperature dependent, indicating that conduction in these films is dominated by carrier hopping through localized states in the intergranular region. SEM studies on Al/Mo 2 N/Si structures revealed the resistance of these films to AlSi interdiffusion. Without any post-deposition annealing treatment, Mo 2 N/Si contacts were found to be perfectly ohmic, with a specific contact resistivity ≈2.6 × 10 3 Ω μm 2 . These characteristics point towards the potential use of this compound as diffusion barrier in Si-based microelectronic devices.

[1]  M. Nicolet,et al.  Properties of reactively sputtered Mo1−xOx films , 1988 .

[2]  M. Nicolet,et al.  WNx: Properties and applications , 1987 .

[3]  P. Ho.  General aspects of barrier layers for very-large-scale integration applications I: Concepts , 1982 .

[4]  R. Hill,et al.  HOPPING CONDUCTION THROUGH LOCALIZED STATES IN Nb/Al$sub 2$O$sub 3$ FILMS. , 1972 .

[5]  P. A. Totta,et al.  SLT device metallurgy and its monolithic extension , 1969 .

[6]  R. H. Cox,et al.  Ohmic contacts for GaAs devices , 1967 .

[7]  S. Kanamori.  Investigation of reactively sputtered TiN films for diffusion barriers , 1986 .

[8]  Contact resistance and methods for its determination , 1983 .

[9]  M. Wittmer,et al.  The use of titanium-based contact barrier layers in silicon technology , 1982 .

[10]  S. Raud,et al.  Performance of W100−xNx diffusion barriers between 〈Si〉 and Cu , 1991 .

[11]  W. Pamler,et al.  Performance and failure mechanisms of TiN diffusion barrier layers in submicron devices , 1989 .

[12]  K. Pourrezaei,et al.  Transmission electron microscopy studies of brown and golden titanium nitride thin films as diffusion barriers in very large scale integrated circuits , 1988 .

[13]  M. Nicolet,et al.  Diffusion barriers in layered contact structures , 1981 .

[14]  Ki-Bum Kim,et al.  Microstructure and barrier properties of reactively sputtered Ti-W nitride , 1990 .

[15]  R. S. Nowicki,et al.  General aspects of barrier layers for very-large-scale integration applications II: Practice , 1982 .

[16]  H. Oikawa,et al.  Electrical resistivity of vaccum‐deposited molybdenum films , 1978 .

[17]  Conduction on localized states in Nb/Al2O3 semiconducting films , 1976 .