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

摘要

The nature and distribution of diamond particulates 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 three materials. The nucleation and growth rate were studied using SEM. In addition, the existence of diamond was verified by XRD analysis and Raman spectroscopy. Deposited diamond particles were detected in all three materials. It has been found that the nucleation and growth rate of diamond particles were rapid on the silicon nitride surface. Raman peaks between 1330-1332 cm~(-1) distinctly shows that sp~3 diamond was successfully deposited on the Si wafer, Si_3N_4 and WC inserts. However, the deposition of diamond crystallites was less homogeneous in both the Si wafer and WC if compared to the Si_3N_4. The presence of sp~2-bonded (graphite) carbon was delected on the Si surface as well as the WC insert. Some of the important parameters controlling the deposition and growth rates of diamond particles are discussed.