Nickel Silicide for Source-Drain Contacts from ALD NiO Films

In this work, we demonstrate the preparation of nickel monosilicide (NiSi) layers on silicon using a conformal NiO ALD process and thin sacrificial Ge interlayers. The interlayers protect the underlying Si from oxidizing during the NiO growth, while allowing for Ni diffusion during a silicidation anneal. The NiSi layers prepared have low amounts of impurities and near bulk resistivities, therefore making the processes promising candidates for applications in advanced semiconductor devices where high quality NiSi layers are needed, such as source-drain contacts. Good step coverage provided by ALD enables their use for example in non-planar transistors such as FinFETs and other multi-gate transistors with complex topographies.