Boron nitride components for MOCVD

Boron Nitride Ceramic parts

Hot-pressed hexagonal Boron Nitride is often referred to as “white graphite” since it has similar layer structure as graphite. It has outstanding thermal characteristics: high thermal conductivity and excellent thermal shock resistance. It is stable up to 2000 °C in reducing atmospheres, and up to 900 °C in oxidizing atmospheres. It has features such as highly machinable, low thermal expansion, microwave transparency and high wet resistance to molten metals, slags and glass. Boron nitride ceramic parts are widely used as PVD, MOCVD, MBE system, furnace components, melting crucibles, insulators, washers, nozzles, microwave tubes, heat sink and heat radiation shielding.

An MOCVD reactor is a chamber made of a material that does not react with the chemicals being used. It must also withstand high temperatures. This chamber is composed of reactor walls, a liner, a susceptor, gas injection units, and temperature control units.

In the MOCVD reactor, the substrate is supported by a pedestal, which also acts as a susceptor. The pedestal/susceptor is the primary origin of heat energy in the reaction chamber. Only the susceptor is heated, so gases do not react before they reach the hot wafer surface. The reaction chamber walls in a cold-wall reactor, however, may be indirectly heated by heat radiating from the hot pedestal/susceptor, but will remain cooler than the pedestal/susceptor and the substrate the pedestal/susceptor supports. So Boron Nitride is a good choice because the power density, operating temperature, insulation grade and dielectric strength of heating elements can be greatly improved by using Boron Nitride as an insulator. It is also more economical and reduces thermal inertia. The annular shape reduces the size of the heating system and improves heat transfer.