9 May 1997 Pulsed laser deposition of boron carbide: spectroscopic study of laser ablation plasma
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Results of emission spectroscopy studies of plasmas produced by pulsed (17 ns) laser irradiation of a boron carbide target are presented. Experiments were performed under conditions typical for the pulsed laser deposition of thin doped diamond- like films. Ablation plasma emission spectra in 300 - 600 nm range were recorded both spatially (0.5 and 0.04 mm) and temporally (20 ns) resolved. Plasma electron temperatures (typically 4 - 2.5 eV) were calculated using intensity ratio of CII ion lines (392 and 437 nm). Electron densities (typically 3 - 1 multiplied by 1019 cm-3) were calculated using Stark broadened lines of CII (392 and 426.7 nm) and BII (412.2 nm). Self-absorption of the emission from the hot core of the plasma by the surrounding cooler shell of the expanding vapor affected the shape of measured emission profiles. A ratio of carbon to boron species in the plasma of approximately 2 derived with an average plasma temperature of 3 eV indicates a surprisingly low concentration of boron in the plasma plume taking into account the target composition B4C. The plasma temperature in the hot inner core of the plume may be even higher. With 5 eV however, the mixing ratio (NC/NB) becomes approximately 0.37, which is close to the target composition. Taking into account steep density and temperature gradients in the plasma and high velocities of plasma expansion one can expect a dramatic variation of concentration ratio of the two species in time and space. An industrial application of laser plasma emission spectroscopy promises to be an effective tool to control the mixing ratio of species, during laser deposition in order to achieve reproducible film composition and quality.
© (1997) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Oleg N. Derkach, Oleg N. Derkach, Simone Pentzien, Simone Pentzien, Wolfgang Kautek, Wolfgang Kautek, } "Pulsed laser deposition of boron carbide: spectroscopic study of laser ablation plasma", Proc. SPIE 2991, Laser Applications in Microelectronic and Optoelectronic Manufacturing II, (9 May 1997); doi: 10.1117/12.273741; https://doi.org/10.1117/12.273741

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