Title :
Ion-energy distributions in Townsend discharges of CHF/sub 3/ at high E/N
Author :
Rao, M.V.V.S. ; Van Brunt, R.J. ; Olthoff, J.K.
Author_Institution :
Nat. Inst. of Stand. & Technol., Gaithersburg, MD, USA
Abstract :
Summary form only given. In this paper we present ion kinetic-energy distributions (IEDs), mean energies, and relative abundances of CF/sub 3//sup +/, CF/sub 2//sup +/, CF/sup +/, CHF/sub 2//sup +/, CH/sup +/, C/sup +/, and H/sup +/ ions produced in DC Townsend discharges in pure CHF/sub 3/. The discharges are generated between two circular parallel-plate electrodes at electric field-to-gas density ratios (E/N) ranging from 5/spl times/10/sup -18/ Vm/sup 2/ to 25/spl times/ 10/sup -18/ Vm/sup 2/ (5 to 25 kTd). A stable discharge could not be attained below 4/spl times/10/sup -18/ Vm/sup 2/ due to the electronegative nature of CHF/sub 3/. Ions sampled from the discharge through a small orifice in the center of the grounded electrode were energy and mass analyzed by a 45/spl deg/ electrostatic energy analyzer attached to a quadrupole mass spectrometer. The present apparatus is equipped with ion optics that allow measurements of ion energies up to 1000 eV.
Keywords :
Townsend discharge; organic compounds; plasma kinetic theory; positive ions; 45/spl deg/ electrostatic energy analyzer; C/sup +/; CF/sub 2//sup +/; CF/sub 3//sup +/; CF/sup +/; CH/sup +/; CHF/sub 2//sup +/; CHF/sub 3/; H/sup +/ ions; Townsend discharges; circular parallel-plate electrodes; electronegative nature; high E/N; ion kinetic-energy distributions; mean energies; quadrupole mass spectrometer; relative abundances; stable discharge; trifluoromethane; Aluminum; Breakdown voltage; Cyclotrons; Electric breakdown; Electrodes; Electron emission; Electrostatic analysis; Plasmas; Radio frequency; Steel;
Conference_Titel :
Plasma Science, 1997. IEEE Conference Record - Abstracts., 1997 IEEE International Conference on
Conference_Location :
San Diego, CA, USA
Print_ISBN :
0-7803-3990-8
DOI :
10.1109/PLASMA.1997.604434
