Nucleation and Growth of Polycrystalline Diamond Particles on Ceramic Substrates by Microwave Plasma CVD

摘要

The nature and distribution of diamondparticulates were studied on three different substrates (Si wafer,Si_3N_4 and WC inserts) using microwave plasma CVD.Deposition was carried out under similar conditions for all threematerials. The nucleation and growth rate were studied usingSEM. In addition, the existence of diamond was verified byXRD analysis and Raman spectroscopy. Deposited diamondparticles were detected in all three materials. It has been foundthat the nucleation and growth rate of diamond particles wererapid on the silicon nitride surface. Raman peaks between 1330-1332 cm~(-1) distinctly shows that sp~3 diamond wassuccessfully deposited on the Si wafer, Si_3N_4 and WC inserts.However, the deposition of diamond crystallites was lesshomogeneous in both the Si wafer and WC if compared to theSi_3N_4. The presence of sp~2-bonded (graphite) carbon wasdetected on the Si surface as well as the WC insert. Some of theimportant parameters controlling the deposition and growthrates of diamond particles are discussed.