Bias enhanced nucleation of diamond on Si(100) in a vertical straight hot filament CVD

The aim of the Bias Enhanced Nucleation (BEN) step is to increase the nucleation density during the CVD diamond growth process with respect to more traditional methods like scratching. Diamond seeds were grown in a HFCVD reactor with several vertical straight filaments and a double bias geometry allowing BEN over large area silicon substrates. The effect of the substrate temperature and the gas composition was studied. Spectroscopic and morphological characterisation has been performed on the substrates, both after the BEN and the subsequent growth process. The substrate temperature was found to be an important parameter controlling the nucleation. When the substrate temperature is above 1100 °C, both the nucleation and the growth resulted in nanocrystalline SiC while at lower temperature optimal diamond nucleation and growth were found. Simultaneously, intermediate phases between elemental and non-stoichiometric SiC were observed by XPS. Nucleation densities of 1011 cm−2 and higher were obtained over a surface of several squared centimeters.