Wsi

WSi commonly denotes tungsten disilicide, a binary inorganic compound of tungsten and silicon. The compound most often has the stoichiometry WSi2, though some literature may use the shorthand WSi to refer to silicide phases associated with silicon; the standard and widely used form in electronics is WSi2.

Properties and structure

WSi2 is a metallic conductor that exhibits high thermal stability and a high melting point. It forms stable silicide interfaces with silicon and silicon dioxide, contributing to robust electrical contacts and diffusion barriers in device layers. The material can be polycrystalline in thin films, with grain size influenced by deposition and annealing conditions.

Production and processing

In semiconductor fabrication, WSi2 can be formed by silicidation of tungsten or by direct deposition of tungsten silicide. Common methods include sputtering tungsten followed by high-temperature annealing to induce reaction with silicon, or chemical vapor deposition (CVD) using silicon- and tungsten-containing precursors (for example, WF6 with silicon-bearing gases) to deposit WSi2 directly. Additional steps may involve patterning and integration with other interconnect materials, such as copper, where WSi2 serves as a diffusion barrier or contact layer.

Applications

The primary use of WSi2 is in microelectronics as a contact material and diffusion barrier in silicon-based devices. Its compatibility with silicon and silicon dioxide, combined with relatively low contact resistivity and good thermal stability, makes it suitable for CMOS interconnects, shallow junctions, and other silicide-based contact schemes. It also features in some MEMS and high-temperature electronics applications where stable metal–silicon interfaces are required.

See also: Silicides, Tungsten, Silicon, Diffusion barriers.

Safety

Handling tungsten silicides generally follows standard chemical safety practices for inorganic solids. Fine powders can pose inhalation hazards or irritate eyes and skin; appropriate engineering controls and personal protective equipment are advised.