PBN Crucibles

Semicorex Pyrolytic Boron Nitride PBN crucibles are precision-engineered components designed to meet the rigorous demands of high-temperature and ultra-pure processes in industries such as semiconductor manufacturing, crystal growth, and vacuum applications. Fabricated through the chemical vapor deposition (CVD) process, PBN crucibles offer superior purity, exceptional thermal stability, and outstanding chemical inertness, making them the material of choice in advanced materials engineering.

Since boron nitride has a thermal expansion coefficient comparable to that of quartz, but its thermal conductivity is 10 times that of the latter, it has excellent thermal shock resistance, which can reduce the risk of cracking due to rapid temperature changes, and can be cycled several times at 20~1200℃ without any problems. In addition, boron nitride does not react with acids, alkalis, glass and most metals, and has low mechanical strength, only slightly higher than graphite, but does not soften under load at high temperatures, and can be processed by general metal processing machines. Therefore, it is indeed suitable for use as a crucible, vessel, liquid metal delivery pipe and mold for steel casting for melting and evaporating metals.

It is usually made by chemical vapor deposition using boron-containing gas (BCl3 or B2H6) as raw material, but because B2H6 is highly toxic, BCl3 is currently used as raw material. The boron-containing gas undergoes pyrolysis (1500~1800℃) and reacts with NH3 in a high-temperature reaction chamber to form solid boron nitride. Because pyrolysis occurs during the reaction, it is also called pyrolytic boron nitride crucible (commonly known as PBN crucibles).

The growth process of the material is similar to "falling snow", that is, the hexagonal BN snowflakes grown in the reaction are constantly piled on the heated graphite substrate (core mold). As time goes on, the accumulation layer thickens, forming a PBN shell. The demolding is an independent, pure PBN component, and the PBN coating is left on it. Since the PBN crucibles do not need to go through the traditional hot pressing sintering process and does not need to add any sintering agent, it has a very high purity (more than 99.99%), and the operating temperature under vacuum is as high as 1800 degrees, and the operating temperature under atmosphere protection can reach up to 2100°C (usually nitrogen or argon). It is mostly used in evaporation/molecular beam epitaxy (MBE)/GaAs crystal growth and other purposes.