Epitaxial growth of uniform NiSi_2 layers with atomically flat silicide/Si interface by solid-phase reaction in Ni-P/Si(100) systems

摘要

As metal-oxide-semiconductor field-effect transistor (MOSFET) devices are shrunk to the nanometer scale, flat shallow metal/Si electrical contacts must be formed in the source/drain region. This work demonstrates a method for the formation of epitaxial NiSi_2 layers by a solid-phase reaction in Ni-P(8 nm)/Si(100) samples. The results show that the sheet resistance remained low when the samples were annealed at temperatures from 400 to 700℃ P atoms can be regarded as diffusion barriers against the supply of Ni to the Si substrate, which caused the formation of Si-rich silicide (NiSi_2) at low temperature. Furthermore, elemental P formed a stable capping layer with O, Ni and Si during the annealing process. A uniform NiSi_2 layer with an atomically flat interface was formed by annealing at 700℃because of the formation of a Si-Ni-P-0 capping layer and a reduction in the total interface area.