Study of sputtered Molybdenum Nitride as a diffusion barrier

Abstract

Molybdenum nitride thin films were deposited using reactive r.f. magnetron sputtering. Single phase gamma-Mo2N 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/Mo2N/Si structures revealed the resistance of these films to Al-Si interdiffusion. Without any post-deposition annealing treatment, Mo2N/Si were found to be perfectly ohmic, with a specific contact resistivity similar to-2.6 x 10(3) Omega mu m(2). These characteristics point towards the potential use of this compound as diffusion barrier in Si-based microelectronic devices.