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 group. In the range 40-120 mTorr, the slow group is characterised by a mean energy E1 approximately equal 0.5 eV and an electron density nsub(e1) approximately equal to 1 x 1011 cm-3; the secondary group has a mean energy E2 approximately equal 7 eV and a density nsub(e2) approximately equal 1 x 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. (author)