Fine Structure of O^-Kinetic Energy Distribution in RF Plasma and Its Formation Mechanism

Abstract

The energy distribution of the negative oxygen (O-) ions ejected from the oxide RF magnetron target is measured by a mass spectrometer including an energy analyzer (QMA-EA). Periodic peaks in O- energy distribution were detected at various experimental conditions. A shift of the peak energies was observed when the distance between the target and the QMA-EA was varied. A model to explain the periodic peaks in the energy distribution was proposed and then validated with experimental results. It was concluded that the periodic peaks are produced by modulation of O- energy distribution due to deceleration of O- ions in the oscillating electric field of the sheath formed in front of the grounded wall.