Tungsten disilicide

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Tungsten disilicide[1]
Identifiers
CAS number 12039-88-2 YesY
PubChem 16212546
Jmol-3D images Image 1
Properties
Molecular formula WSi2
Molar mass 240.011 g/mol
Appearance blue-gray tetragonal crystals
Density 9.3 g/cm3
Melting point 2160°C
Solubility in water insoluble
Hazards
EU Index not listed
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point Non-flammable
Related compounds
Other anions Tungsten carbide
Tungsten nitride
Other cations Molybdenum disilicide
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

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

Chemistry[edit]

Tungsten silicide can react violently with substances such as strong acids, fluorine, oxidizers, and interhalogens.

Applications[edit]

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, e.g. 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.[2] 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 e.g. nitrogen trifluoride gas.

References[edit]

  1. ^ Lide, David R. (1998), Handbook of Chemistry and Physics (87 ed.), Boca Raton, FL: CRC Press, pp. 4–91, ISBN 0-8493-0594-2 
  2. ^ [1]