A. Bogaerts et al., 3-DIMENSIONAL DENSITY PROFILES OF SPUTTERED ATOMS AND IONS IN A DIRECT-CURRENT GLOW-DISCHARGE - EXPERIMENTAL-STUDY AND COMPARISON WITH CALCULATIONS, Spectrochimica acta, Part B: Atomic spectroscopy, 52(2), 1997, pp. 205-218
Three-dimensional density profiles of the sputtered tantalum atoms and
ions have been measured in a direct current glow discharge with flat
cathode, by laser induced fluorescence spectroscopy. The primary excit
ation lines of the tantalum atoms and ions are taken to be the 269.131
nm and the 270.280 nm lines, respectively, whereas the 358.42 nm line
and the 304.2 nm line are used as their fluorescence lines, respectiv
ely. Moreover, atomic absorption measurements with a hollow cathode la
mp were also performed to check the fluorescence results for the atoms
. The 271.467 nm line was selected for this purpose. The discharge was
studied for a range of voltages, pressures and currents (i.e. 700-120
0 V, 0.7-1.6 torr, 1.2-3.9 mA). The atom density profile reaches a max
imum at about 3 mm from the cathode, whereas the ion density profile w
as found to be at its maximum at about 6 mm from the cathode. The expe
rimental data have been compared with results of mathematical simulati
ons for the same geometry; in general, satisfactory agreement is reach
ed. Experimental observations and modeling calculations allow better i
nsight into the complex interactions occurring in a glow discharge. (C
) 1997 Elsevier Science B.V.