AVS 47th International Symposium
    Plasma Science and Technology Wednesday Sessions
       Session PS-WeP

Paper PS-WeP10
Langmuir Probe Measurements in an Inductively Coupled Ar/CF@sub 4@ Plasmas

Wednesday, October 4, 2000, 11:00 am, Room Exhibit Hall C & D

Session: Poster Session
Presenter: M.V.V.S. Rao, NASA-Ames Research Center
Authors: M.V.V.S. Rao, NASA-Ames Research Center
M. Meyyappan, NASA-Ames Research Center
S.P. Sharma, NASA-Ames Research Center
Correspondent: Click to Email
Technological advancement in the microelectronics industry requires an understanding of the physical and chemical processes occurring in plasmas of fluorocarbon gases, such as carbon tetrafluoride (CF@sub 4@) which is commonly used as an etchant, and their mixtures to optimize various operating parameters. In this paper we report data on electron number density (n@sub e@) temperature (T@sub e@) ion energy distribution function (EEDF), mean electron energy, ion number density (n@sub i@), and plasma potential (V@sub p@) measured by using Langmuir probe in an inductively coupled 13.56 MHz radio frequency plasmas generated in 50%Ar:50%CF@sub 4@ mixture in the GEC cell. The probe data were recorded at various radial positions providing radial profiles of these plasma parameters at 10-50 mTorr pressures and 200 W and 300 W of RF power. Present measurements indicate that the electron and ion number densities increase with increase in pressure and power. Whereas the plasma potential and electron temperature decrease with increase in pressure, and they weakly depend on RF power. The radial profiles exhibit that the electron and ion number densities and the plasma potential peak at the center of the plasma with an exponential fall away from it, while the electron temperature has a minimum at the center and it increases steadily towards the electrode edge. The EEDFs have a characteristic drop near the low energy end at all pressures and powers, and their shapes represent non-Maxwellian plasma and exhibit more like Druyvesteyn energy distribution.