Tungsten(IV) silicide

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Tungsten(IV) silicide
Image:Tungsten(IV) silicide.jpg
Other names	tungsten(IV) disilylenide tungsten(IV) disilenide tungsten disilicide
Identifiers
CAS number	[12039-88-2]
Properties
Molecular formula	WSi2
Molar mass	240.02 g/mol
Appearance	blue odorless powder
Density	9.4 g/cm³, solid
Melting point	2437 K (2164 °C)
Solubility in water	insoluble
Hazards
EU classification	not listed
NFPA 704	0 1 0
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Tungsten(IV) silicide, or just tungsten silicide (WSi₂) is an inorganic compound, a silicide of tungsten. It is a ceramic material. It is electrically conductive. It is a very hard solid material.

It is used in microelectronics as a contact material, with resistivity 60-80 μΩ-cm; it forms at 1000 °C. It is often used as a shunt over polysilicon lines to increase their conductivity and increase signal speed. Tungsten silicide layers can be prepared by chemical vapor deposition, eg. using monosilane or dichlorosilane with tungsten hexafluoride as source gases. The deposited film is non-stoichiometric, and requires annealing to convert to more conductive stoichiometric form. Tungsten silicide is a replacement for earlier tungsten films. [1] Tungsten silicide is also used as a barrier layer between silicon and other metals, e.g. tungsten.

Tungsten silicide also finds use in microelectromechanical systems and for oxidation-resistant coatings.

Films of tungsten silicide can be plasma-etched using eg. nitrogen trifluoride gas.

Tungsten nitride is another material with similar use.

Tungsten silicide can react violently with substances like e.g. strong acids, fluorine, oxidizers, and interhalogens.

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