Energy distribution function of substrate incident negative ions in magnetron sputtering of metal-doped ZnO target measured by magnetized retarding field energy analyzer

Abstract

The energy distribution function of the substrate incident negative ions during magnetron sputtering of a metal-doped zinc oxide target was measured using a home-made retarding field energy analyzer (RFEA) with a magnetic field region. The cross-field region in front of the RFEA injection aperture allows the bulk electrons in the plasma into the RFEA are dramatically suppressed, while the inflow of negative ions emitted from the oxide target is largely unaffected. Negative ions were found to be mainly emitted from the target erosion area and incident on the opposing substrate with ion energy equivalent to the target applied voltage. Compared to energy-resolved mass spectrometers, which require differential pumping and are large and not very portable, magnetized RFEA is inexpensive, compact and easy to sweep in space, although there is no mass separation.