Interaction of Mo/Ni and Mo/Co bilayer structures with silicon

Abstract

The thin film interaction of Mo/Ni and Mo/Co bilayer structures was investigated in the temperature range 500-650 °C by Auger electron spectroscopy and glancing angle X-ray diffraction. It was observed that (i) the silicide formation temperature is lowered, (ii) the rate of silicon diffusion is enhanced and (iii) hindrance due to the natural SiO_x layer is avoided by interposing a thin layer (approximately 100 Å) of nickel-cobalt between the molybdenum and silicon. The temperature of formation of MoSi₂ (tetragonal phase) was found to be approximately 500-550 °C. The reaction mechanism and the role of the interlayer is discussed on the basis of various reaction temperatures and moving species (nickel, cobalt and silicon) during silicide formation.