Formation of nickel silicide from direct-liquid-injection chemical-vapor-deposited nickel nitride films

Abstract

Smooth, continuous, and highly conformal nickel nitride (NiNx) films were deposited by direct liquid injection (DLI)-chemical vapor deposition (CVD) using a solution of bis(N, N′ -di- tert -butylacetamidinato) nickel(II) in tetrahydronaphthalene as the nickel (Ni) source and ammonia (NH3) as the coreactant gas. The DLI-CVD NiNx films grown on HF-last (100) silicon and on highly doped polysilicon substrates served as the intermediate for subsequent conversion into nickel silicide (NiSi), which is a key material for source, drain, and gate contacts in microelectronic devices. Rapid thermal annealing in the forming gas of DLI-CVD NiNx films formed continuous NiSi films at temperatures above 400°C. The resistivity of the NiSi films was 15 μ cm, close to the value for bulk crystals. The NiSi films have remarkably smooth and sharp interfaces with underlying Si substrates, thereby producing contacts for transistors with a higher drive current and a lower junction leakage. Resistivity and synchrotron X-ray diffraction in real-time during annealing of NiNx films showed the formation of a NiSi film at about 440°C, which is morphologically stable up to about 650°C. These NiSi films could find applications in future nanoscale complementary metal oxide semiconductor devices or three-dimensional metal-oxide-semiconductor devices such as Fin-type field effect transistors for the 22 nm technology node and beyond. © 2010 The Electrochemical Society.