Theoretical and experimental research on growth and doping mechanisms of diamond films fabricated using liquid carbon source precursors

Fabricating diamond films using liquid carbon source precursors in hot filament chemical vapor deposition (HFCVD) is an emerging technology. Although some experiments have demonstrated the feasibility of depositing doped diamond films using liquid carbon source precursors such as acetone, the theoretical explanation still needs to be elucidated. In this study, the density functional theory (DFT) method was used to analyze the decomposition and adsorption processes of acetone and methane on the surface of a diamond (1 1 1) models and to clarify the advantages of liquid carbon source precursors. The decomposition and adsorption reaction processes of trimethyl borate, urea, and ethyl orthosilicate on the surface of diamond (1 1 1) model were also analyzed to elucidate the doping mechanisms of B, N, and Si elements. Additionally, undoped diamond films were fabricated using acetone and methane precursors, illustrating that liquid precursors have higher growth rates than gas precursors. B-, N-, and Si-doped diamond films were also fabricated using liquid-doped carbon source precursors. Element detection by TOF-SIMS illustrates that all three elements had been doped into the diamond films and were uniformly distributed. Conversely, no doping elements were detected in N-doped diamond film fabricated with nitrogen and methane precursors.

Automated summary

Fabricating diamond films using liquid carbon source precursors in hot filament chemical vapor deposition (HFCVD) is an emerging technology. The density functional theory (DFT) method was used to analyze the decomposition and adsorption processes of acetone and methane on the surface of a diamond (1 1 1) models and to clarify the advantages of liquid carbon source precursors. The doping mechanisms of B, N, and Si elements were also analyzed by studying the decomposition and adsorption reaction processes of trimethyl borate, urea, and ethyl orthosilicate on the surface of diamond (1 1 1) model.