disilicides

Disilicides are binary intermetallic compounds consisting of silicon and a more electropositive element, with the empirical formula MSi2, i.e., one metal atom for every two silicon atoms. They are a subclass of silicides and cover a range of metals from transition metals to main-group elements.

Disilicides form by direct reaction of silicon with the metal at elevated temperatures, or by deposition methods such as chemical vapor deposition, physical vapor deposition, or solid-state reactions from metal and silicon precursors. Their crystal structures vary with the metal, and many adopt intermetallic frameworks that confer high thermal stability.

The electrical behavior of disilicides ranges from metallic to semiconducting. Some, like FeSi2, are narrow-gap semiconductors with thermoelectric potential; others, such as MoSi2 and TiSi2, are metallic and valued for high-temperature stability and oxidation resistance.

They are used as contact and diffusion-barrier materials for silicon-based microelectronics, as well as high-temperature structural materials. In some cases, disilicides also serve as heating elements or thermoelectric materials. Specific disilicides, including CrSi2, NiSi2, CoSi2, TiSi2, and MoSi2, have been studied for these roles.

Notes: The properties and structure can be strongly affected by non-stoichiometry, defects, and processing conditions. Because the term covers many compounds with diverse chemistries, precise properties must be assessed per compound.