Tungsten disilicide
| Tungsten disilicide[1] | ||
|---|---|---|
| IUPAC name Tungsten disilicide | ||
| Identifiers | ||
| CAS number | 12039-88-2  | |
| PubChem | 16212546 | |
| Jmol-3D images | {{#if:[Si]#[W]#[Si]|Image 1 | |
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| 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 |
 0
1
0
| |
| Flash point | Non-flammable | |
| Related compounds | ||
| Other anions | Tungsten carbide Tungsten nitride | |
| Other cations | Molybdenum disilicide | |
(verify) (what is: / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa) | ||
| 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
Tungsten silicide can react violently with substances such as strong acids, fluorine, 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, 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
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