Characterisation of Electroless Deposited Cobalt by Hard and Soft X-ray Photoemission Spectroscopy

Electroless deposited (ELD) cobalt with palladium as a catalyst, and an underlying self-assembled monolayer (SAM) was investigated for potential use in advanced complementary metal oxide semiconductor (CMOS) applications using both hard (HAXPES) and soft (XPS) x-ray photoelectron spectroscopy. HAXPES spectra established the uniformity of the deposited Co film and the nature of the buried Co-Si interface ~20nm below the surface. The Pd is seen to diffuse through the Co following thermal annealing. While the deposited Co film is predominantly metallic, Co-silicide forms at the Co-Si interface upon deposition and decomposes with thermal anneal up to 500°C.