Secondary Ion Emission from Metal Targets under CF₃⁺ and O₂⁺ Bombardment

Abstract

CF3+ has been extracted from a cold cathode Ion gun supplied with a CF4/N2 gas mixture. A CF3+ beam current of about 200 nA Is obtained, which Is about a factor of 5 smaller than the ~1 µA O2+ beam currents obtainable from conventional oxygen Ion sources. This decrease Is partially offset by the higher sputter yields obtained with CF3+. Ionization probabilities are higher or equal to those found for O2+ bombardment. Composition and chemical state analyses were performed after saturation bombardment. Generally metal carbides are found to have formed with a fluorine uptake of about 10-20 atom %. The fluorine Is bonded to the metal. Matrix effects are smaller under O2+ bombardment due to the low fluorine concentration. © 1987, American Chemical Society. All rights reserved.