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

Chemistry

Tungsten silicide can react violently with substances such as strong acids,

fluorine Fluorine is a chemical element with the symbol F and atomic number 9. It is the lightest halogen and exists at standard conditions as a highly toxic, pale yellow diatomic gas. As the most electronegative reactive element, it is extremely reacti ...

, oxidizers, and interhalogens.

Applications

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 Chemical vapor deposition (CVD) is a vacuum deposition method used to produce high quality, and high-performance, solid materials. The process is often used in the semiconductor industry to produce thin films. In typical CVD, the wafer (substra ...

, e.g. using monosilane or dichlorosilane with

tungsten hexafluoride Tungsten(VI) fluoride, also known as tungsten hexafluoride, is an inorganic compound with the formula W F6. It is a toxic, corrosive, colorless gas, with a density of about (roughly 11 times heavier than air). It is one of the densest known gase ...

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. Tungsten silicide is also used as a barrier layer between silicon and other metals, e.g. tungsten. Tungsten silicide is also of value towards use in

microelectromechanical systems Microelectromechanical systems (MEMS), also written as micro-electro-mechanical systems (or microelectronic and microelectromechanical systems) and the related micromechatronics and microsystems constitute the technology of microscopic devices, ...

, where it is mostly applied as thin films for fabrication of microscale circuits. For such purposes, films of tungsten silicide can be plasma-etched using e.g.

nitrogen trifluoride Nitrogen trifluoride () is an inorganic, colorless, non-flammable, toxic gas with a slightly musty odor. It finds increasing use within the manufacturing of flat-panel displays, photovoltaics, LEDs and other microelectronics. Nitrogen trifluori ...

gas. WSi₂ performs well in applications as oxidation-resistant coatings. In particular, in similarity to Molybdenum disilicide, MoSi₂, the high emissivity of tungsten disilicide makes this material attractive for high temperature radiative cooling, with implications in

heat shield In thermodynamics, heat is defined as the form of energy crossing the boundary of a thermodynamic system by virtue of a temperature difference across the boundary. A thermodynamic system does not ''contain'' heat. Nevertheless, the term is al ...

s.High emissivity coatings on fibrous ceramics for reusable space systems
Corrosion Science 2019

References

{{Silicides Ceramic materials Group 6 silicides Refractory materials Semiconductor materials Tungsten compounds