ELECTRON-ENERGY DISTRIBUTIONS IN A SPUTTERING DISCHARGE

The electron energy distributions of slow and secondary electrons in the negative glow of an argon sputtering discharge with a titanium cathode have been studied with single probes and grid probes. Measurements have shown that the distributions are generally of the Druyvesteyn type for the two electrons groups. In the range 40-120 mTorr, the slow group is characterised by a mean energy (E1) approximately=0.5 eV and an electron density n e1 approximately=1*1011 cm-3; the secondary group has a mean energy (E2) approximately=7 eV and a density ne2 approximately=1*109 cm-3. These values are dependent on the discharge parameters and are mainly influenced by the pressure for the slow group and by the discharge power for the secondary group.