Effect of neon mixing on vibrational temperature of molecular nitrogen plasma generated at 13.56 MHz

Optical emission spectroscopy is used to investigate the effect of neon mixing on the electron temperature and vibrational temperature of second positive and first negative system of nitrogen plasma generated by 13.56 MHZ RF generator. The electron temperature is determined from Ne-I lines intensities, using Boltzman's plot. The relative changes in vibrational population of N-2(C-3 Pi(u)) and N-2(+) (B-2 Sigma(+)(u)) monitored by measuring the emission intensities of second positive and first negative system of nitrogen molecules. Vibrational temperature is calculated for the sequences Delta nu = 0, 1, -2, that follows the Boltzman's distribution. It is found that electron temperature as well as vibrational temperature of second positive and first negative system can be raised significantly by mixing neon in nitrogen plasma. Vibrational temperature at 250 watt RF power, of second positive system is raised up to 0.67 eV at 90% neon where as for first negative system it is raised up to 0.78 eV. It is found that vibrational temperature increases with the gas pressure. (c) 2007 Elsevier B.V. All rights reserved.