Tungsten silicide
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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 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, eg. 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.
