Ion-energy distributions in Townsend discharges of CHF/sub 3/ at high E/N

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.