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Langmuir probe

In thin  film deposition processes, a precise knowledge of plasma characteristics is critical. The physical plasma properties can be studied with a Langmuir probe which is a plasma diagnostics tool consisting in a small wire inserted in the plasma chamber.

During the process the current (I) as function of applied voltage (V) is measured. Analyzing the measured I/V curves the following plasma parameters can be estimated:

  • the plasma potential (Vp)
  • the floating potential(Vf)
  • the ionic / electronic current
  • the electron/ionic density
  • the electron temperature