Emissive probe measurements of plasma potentials outside the source aperture of an electron cyclotron resonance etching device have shown large radial electric fields in a nitrogen discharge. It is shown that the magnitude of the radial electric field is pressure dependent, decreasing for higher pressures. In addition to radial and axial profiles of the plasma potential, profiles of ion density, electron temperature, and floating potential were measured with Langmuir probes for several cases: Two magnetic‐field configurations, with and without an insulating liner in the source, and with and without a wafer stage. It is shown that the plasma potential with the liner present is higher when there is a resonance zone close to the aperture of the source, as opposed to when the resonance zone is farther inside the source.

http://dx.doi.org/10.1116/1.578546