DOUBLE AND TRIPLE LANGMUIR PROBES MEASUREMENTS IN INDUCTIVELY COUPLED NITROGEN PLASMA

The double and triple Langmuir probe diagnostic systems with their necessary driving circuits are developed successfully for the characterization of laboratory built low pressure inductively coupled nitrogen plasma, generated by 13.56 MHz radio frequency (RF) power supply along with an automatic impedance matching network. Using the DC properties of these two probes, the discharge plasma parameters like ion saturation current (Iio), electron temperature (kTe) and electron number density (ne) are measured at the input RF power ranging from 250 to 400 W and filling gas pressures ranging from 0.3 to 0.6 mbar. An increasing trend is observed in electron temperature kTe and ne with the increase of input RF power at a fixed filling gas pressure of 0.3 mbar, while a decreasing trend is observed in kTe and ne with the increase of filling gas pressure at a fixed input RF power of 250 W.