Surface observation of beta-SiC substrate after negative bias treatment in diamond deposition

Recently, high oriented texture growth of diamond thin films on beta-SiC has been obtained by the bias-enhanced-nucleation (BEN) method in a microwave plasma-assisted chemical vapor deposition (MPCVD) system. Negative bias treatment, as process of nucleating diamond, is an important process. However, there are a lot of unknown matters in the nucleation process of diamond, We here focused our attention on the interface between (100) beta-SiC substrate and grown diamond film. In this study, we exposed beta-SiC substrates to (H-2 + CH4) plasma during the negative bias application, and found that the beta-SiC layer is markedly etched off during this treatment. Nevertheless, once the amorphous ultra-thin layer was formed by a carbonization procedure in advance, there was no sign of beta-SiC etching even for negative bias treatment, and moreover this significantly enhances nucleation of diamond on it. In addition, we demonstrated the effect of xenon additive to (H-2 + CH4) plasma, which increased the deposition rate of diamond films. This might promise mild diamond growth and save the Interface from the plasma damage.