ION FORMATION PROCESSES IN THE AFTERPEAK TIME REGIME OF PULSED GLOW-DISCHARGE PLASMAS

The formation of ions following the termination of power in a pulsed g low discharge ion source is investigated. The populations of ionized s pecies containing sputtered atoms M+, M2+, and MAr+ are observed to ma ximize after the termination of discharge power. Collisions involving sputtered atoms and metastable argon atoms, Penning and associative io nization, are considered to be responsible for the formation of ions i n the discharge afterpeak time regime. The domination of these ion for mation processes during the afterpeak time regime is supported by the results from investigations of discharge operating parameters, metasta ble argon atom quenching, and ion kinetic energy distributions.