Silicides and nitrides formation in Ti films coated on Si and exposed to (Ar-N 2 -H 2 ) expanding plasma

Abstract

The physical properties including the mechanical, optical and electrical properties of Ti nitrides and silicides are very attractive for many applications such as protective coatings, barriers of diffusion, interconnects and so on. The simultaneous formation of nitrides and silicides in Ti films improves their electrical properties. Ti films coated on Si wafers are heated at various temperatures and processed in expanding microwave (Ar-N 2 -H 2 ) plasma for various treatment durations. The Ti-Si interface is the centre of Si diffusion into the Ti lattice and the formation of various Ti silicides, while the Ti surface is the centre of N diffusion into the Ti film and the formation of Ti nitrides. The growth of silicides and nitrides gives rise to two competing processes which are thermodynamically and kinetically controlled. The effect of thickness on the kinetics of the formation of silicides is identified. The metastable C 49 TiSi 2 phase is the main precursor of the stable C 54 TiSi 2 phase, which crystallizes at about 600 °C, while TiN crystallizes at about 800 °C.