The validity of oes line-ratio method to determine the electron temperature in inductively coupled nitrogen plamas

Summary form only given. The validity of the line-ratio method to determine the electron temperature in inductively coupled nitrogen plasmas using optical emission spectroscopy is investigated in the pressure range 0.4-100 milli-torr. It is found that when the pressure is higher than several mtorr, the linear kinetic processes of metastable nitrogen molecules, such as collisions of them with the vibrationally excited levels of the ground state, play an important role and the corona model is not correct. When the pressure higher than several tens of milli-torr, the non-linear kinetic processes of metastable molecules, such as the energy pooling reaction between two of them, become important and thus the line intensity is not in direct proportion to the electron density and the line-ratio has a significant dependence on electron density