Characterization of a high-density electron-cyclotron resonance plasma source operating in nitrogen

Parametric characterization of a low-pressure and high-density electron-cyclotron resonance plasma source operating in nitrogen over a range of low-pressure 10(-3)-10(-4) mbar, dissipated power 500 W, and magnetic field intensity 200-400 G, is presented. Internal parameters like electron energy distribution function, plasma density, electron temperature, plasma potential, and floating potential, were measured using a compensated Langmuir probe. The radial variation of internal parameters evidences two discharge modes, that is, a constricted mode for low-magnetic field values and a diffuse mode for high-magnetic field values. The electron energy distribution function is Maxwellian within the energy range of 0-15 eV and presents a structure with two prominent dips around 3.5 and 9.0 eV. The form of the structure and the position of the dips do not change significantly with the radial position or by changing the external parameters. (C) 2003 American Institute of Physics.