Novel technique for hetero-epitaxial diamond film growth on cubic boron nitride from iron carbide at high temperature and high pressure

Cubic boron nitride (c-BN) crystals about 0.1-0.3mm in dimension were treat ed with iron carbide powders (high purity 99%) with size of 80-100 mesh at a high temperature of 1620 K and a high pressure of 5.2 GPa. It was found t hat hetero-epitaxial diamond films have been grown on the c-BN from iron ca rbide. The formation of diamond films on the cubic boron nitride can be con firmed by laser Raman spectra, face scan of elements and reflective high-en ergy electron diffraction. It was suggested that diamond films could be epi taxially formed on the c-BN through decomposition of iron carbide. This app roach provides a possible and very effective way to realize hetero-epitaxia l growth of homogeneous and large-area diamond films on c-BN, which is diff erent from the conventional technique using a chemical vapor deposition met hod.