Influence of Atomic Hydrogen on Nickel Silicide Formation

Abstract

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.

Specific contact resistivity of Al-NiSi contacts using Cross Kelvin Resistor test structure chains

“…These advantages make NiSi attractive for shallow junction CMOS process technologies. Most published literature report nickel silicide formation by Rapid Thermal Processing (RTP) 7,8,9 . With regard to the CMOS process flow, the self-aligned silicide process would be performed after defining the transistor terminals and junctions.…”