Testing of nickel-chrome alloy as a tip material for multi-tip langmuir probes

The electrostatic probes are considered to be the most powerful and experimentally simplest technique for plasma characterization. The objective of the work was to test the nickel-chrome alloy as probe tip material for characterization of RF discharge plasmas. In order to meet the objective, a triple Langmuir probe diagnostic system and associated driving circuit was designed and tested in inductively coupled plasma (ICP) generated by a 13.56 MHz radio frequency (RF) source. Using this probe diagnostic, the electron temperature, electron number density and ion saturation current were measured as a function of input RF power and filling gas pressure. An increasing trend was noticed in electron temperature and electron number density with input power whilst a decreasing trend was evident in these parameters for increasing nitrogen gas pressure. The overall variations in electron temperature and electron number density after repeated measurements were ranging from 5 to 12 and 3 to 13, respectively. © 2014 World Scientific Publishing Company.