GROWTH OF CUBIC BORON-NITRIDE BY CHEMICAL-VAPOR-DEPOSITION AND HIGH-PRESSURE HIGH-TEMPERATURE SYNTHESIS

With respect to its exceptional physicochemical properties, cubic boron nitride (c-BN) is closely related to diamond; it is a III-V compound with potential electronic developments in the near future. The high thermal stability of c-BN and its ability to avoid being transferred into ferrous alloys during high-speed tooling make it a sought after material. A general survey of the two main routes used for synthesis is presented: the high-pressure high-temperature synthesis (HP-HT) and chemical vapor deposition (CVD). The former is mainly used for the production of microcrystallites for dense ceramics, PCBN products or single crystals. Since c-BN can be n or p doped more easily than diamond, the second route is now being developed to prepare doped thin films for microelectronic applications. A projection of the developments of c-BN is given on the basis of potential applications in different industrial domains. In addition, the future of c-BN is analyzed on the basis of the latest thermodynamic calculations claiming that this structural form is stable at normal pressure if the temperature is lower than 1000-degrees-C.