A spectroscopic study of active species in DC and HF flowing discharges in N-2-H-2 and Ar-N-2-H-2 mixtures

Optical emission spectroscopy and laser-induced fluorescence (LIF) techniques are used to study the production of active species in DC and HF N-2-H-2 and N-2-H-2-Ar flowing discharges and post-discharges, in connection with plasma reactions for surface treatments. N and H ground state atom relative densities are obtained by two-photon LIF in a N-2-H-2 flowing DC discharge and in the DC and HF post-discharge regions. The conditions to create maximum density of N and H species are determined in each case in relation to the plasma kinetics. In no case was the NH radical observed in the post-discharge regions, indicating that this radical does not contribute to the nitriding process.