Magnetron discharge with azimuthally nonuniform W-Be cathode

The work presents results of discharge characteristics studies in crossed E-H fields of a planar magnetron filled with deuterium and using different materials of the cathode-target whose secondary ion-electron emission coefficients differ essentially. It was found that voltages at which discharge takes place differ substantially for beryllium and tungsten. The discharge voltage for beryllium cathode is relatively small and varies weakly over a wide range of condition changes. The current-voltage relations (CVR) of a discharge with a tungsten cathode, on the contrary, is "classic"-the discharge voltage is considerably higher and substantially depends on external parameters. The results of magnetron discharges studies with a composite cathode incorporating sectors made of different materials are being presented as well. The authors note that an azimuthal drift in the crossed fields results in an efficient "mixing" of emission electrons knocked-on from different target materials. The dynamics of CVR modification was studied too. Relative redeposition of. sputtered target atoms under operating pressure was revealed experimentally, and a theoretical interpretation of this effect was carried out.