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