Influence of atomic hydrogen on nickel silicide formation

Nickel monosilicide (NiSi) is a leading contender to replace the currently used class of silicides for contacts to the source, drain and gate regions in Complimentary Metal-Oxide-Semiconductor (CMOS) circuits. In this work, the effect of substrate hydrogenation by a hydrogen plasma treatment prior to nickel deposition and silicidation was studied. The sheet resistance of the silicide film shows a significant decrease under hydrogenation of the Si substrate prior to Ni evaporation/anneal for projected silicidation temperatures below 600°C. Correspondingly, the Si region near the interface is decorated with defects. At higher silicidation temperatures, the sheet resistance rises along with greater in-diffusion of Ni into the hydrogenated Si samples. Secondary Ion Mass Spectrometry, Transmission Electron Microscopy and Hall effect measurements are used to characterize the samples.