Nitrides

Abstract

Nitrides may be classified as being ionic or salt‐like, metallic, nonmetallic (diamond‐like) or volatile. The properties of transition‐metal metallic nitrides and the diamond‐like nonmetallic nitrides are described. Additionally, sulfur and phosphorus form polymeric nitride species. Transition‐metal binary nitrides, made on a small scale, are used for high strength and hardness primarily as refractory coatings. Boron, aluminum, and silicon nitrides find use as refractories, ablative materials, abrasives, and coatings. The combination of high thermal conductivity, high electrical resistivity and linear thermal expansion coefficient makes aluminum nitride a sufficient ceramic material for electronic applications. Several powder‐specific synthesis methods for aluminum nitride are described and the effects of oxygen and impurity contamination are mentioned. Lithium nitride finds application in batteries and catalysts. Gallium and indium nitrides are used in such optoelectronic devices as light‐emitting diodes. The material and electrical properties of gallium nitride (GaN) position it as a prime candidate for high power microwave applications. GaN has shown extensive potential in the microelectronics environment for high electron mobility transistors. The manufacture and processing of nitride coatings by case hardening is presented as well as the processing of the structurally important silicon nitride. A brief summary of the optical and electronic properties, including optical adsorption and field emission, of carbon nitride are also presented. Plasma enhanced and hot filament chemical vapor deposition techniques are highlighted as two of the most current preparation methods used to obtain carbon nitride films.