Evidence of silicide at the Ni/beta-Si3N4(0001)/Si(111) interface

We present a study of a sub-nanometer interlayer of crystalline silicon nitride at the Ni/Si interface. We performed transmission electron microscopy measurements complemented by energy dispersive X-ray analysis to investigate to what extent the nitride layer act as a barrier against atom diffusion. The results show that discontinuous silicide areas can form just below the nitride layer, whose composition is compatible with that of the nickel disilicide. The Ni-Si reaction is tentatively attributed to the thermal strain suffered by the interface during the deposition of Ni at low temperature.