Measurements of electron energy distribution function and neutral gas temperature in an inductively coupled plasma
Inductively coupled plasma (ICP) is a promising low pressure, high density plasma source for material processing and is of great importance to modern plasma technology. This thesis summarizes the results of experimental study in a cylindrical ICP by using a single Langmuir probe (LP) and optical emission spectroscopy (OES). The electron energy distribution function (EEDF), which contains important information of ICP plasma and is necessary for an accurate kinetic description of the low-pressure discharges, has been investigated with the Langmuir probe by using the alternating current (ac) method. Measurements were carried out in different gases including both atomic (argon, helium) and molecular (hydrogen, nitrogen) gases. The effects of the external discharge parameters such as gas pressure and radio frequency (rf) power have been investigated and the different mechanisms that influence the formation of the EEDF have been discussed. The radial dependence of the EEPF in the argon plasma has also been evaluated. The average electron energy and electron density have also been obtained by direct measurement of the electron current-voltage (I-V) curve and the result is consistent with the power balance equation. Optical emission spectroscopy has been used to study the importance of neutral gas heating in the ICP. The method used is based upon simulating and fitting the nitrogen emission band (the transition from,uCΠ30'=V to,gBΠ30"=V). Both nitrogen and argon plasmas have been studied separately and significant neutral heating has been found.
DegreeMaster of Science (M.Sc.)
DepartmentPhysics and Engineering Physics
ProgramPhysics and Engineering Physics
Copyright DateAugust 2006
Neutral Gas Temeprature