Structural characterization of in-situ silicided contacts textured on p-type [001] silicon

Nickel silicide is widely used to realize contact terminals of integrated circuits and is usually formed by ex-situ heating treatments. In-situ reactions during sputter depo- sition of a Ni layer onto a HF p-type [001] Si substrate have been investigated in this work, by means of trans- mission electron microscopy, X-ray diffraction and X-ray reflectivity analyses. A thin layer of polycrystalline sili- cide, with extremely flat interfaces and in fiber texture with the Si substrate, has been obtained by introducing a sputter etching step just before Ni deposition and prop- erly modulating its duration. The work has also been aimed to decouple the thermal impact of sputter etching from its effect on surface cleaning, disclosing its key role in the whole reaction process. Cross-sectional TEM analysis of a nickel silicide layer, formed by in-situ solid-state reaction, showing an ex- tremely flat interface with the Si substrate.