Aluminum nitride (AlN, Figure 1) is a synthetic ceramic with a unique combination of useful thermal and electrical properties. Chief among them are high thermal conductivity, excellent dielectric properties, low coefficient of thermal expansion (close to silicon), nontoxicity, and chemical- and high-temperature resistance. Also, AlN is a high bandgap semiconductor, so there is growing interest developing around AlN powders for single crystal growth.

Although AlN has been known for more than a century, interest has renewed in the recent decade or so. AlN is more expensive than alumina, which is used for many substrate and dielectric applications. Alumina, however, cannot meet the requirements for many high-brightness LED and power electronics applications. The dramatic growth of these new technologies also drives growing demand for polycrystalline sintered AlN products. Moreover, the relentless push for faster speed, smaller footprint, and high power density of microprocessor chips in the optoelectronic and power electronic industries fuels demand for advanced heat-dissipation solutions.