Reactive expansion of laser-induced boron/carbon plasma in ECR nitrogen plasma during the deposition of BCN films

The expansion of the boron/carbon plasma induced by pulsed laser ablation of B4C in the nitrogen plasma generated by electron cyclotron resonance (ECR) microwave discharge of N2 gas was studied by optical emission spectroscopy (OES). OES measurements show that at the initial stages the mono-atomic species ablated from B4C are the dominant emitting species and after 0.5 μs the plasma emission evolves to be dominated by the emission bands from nitrogen molecules and nitrogen molecular ions, revealing that the N2 gas is highly excited by the hybrid processes of ECR microwave discharge and pulsed laser ablation. In addition to the emissions emitted from the species ablated from the target and present in the reactive background, C2 and CN emissions are also observed. The characteristics of the emissions from various species provide an access to the reactive expansion of the boron/carbon plasma in the nitrogen plasma and the gas-phase reactions occurring in the plasmas during the deposition of BCN films by nitrogen plasma assisted pulsed laser deposition. The mechanisms for efficient incorporation of nitrogen in the films were also discussed.

► We study the interactions between PLA boron/carbon plasma and ECR nitrogen plasma. ► N2 gas discharge and B4C ablation together result in highly reactive plasma. ► CN emission is observed in addition to the emissions from other emitting species. ►The gas-phase reactions are discussed based on the analysis of the plasma emission. ►We discuss the mechanisms for BCN deposition by the ECR discharge and PLA processes.