Effect of secondary electrons and negative ions on sputtering of films

Experiments have been carried out to determine quantitatively the effects of the bombardment of a growing film by secondary electrons and negative ions emitted at a target. The secondary electrons have been found to depress deposition rates and to cause changes in composition of the films. This effect takes place apparently by biasing the substrate negatively by secondary electrons and subsequent resputtering by Ar+ ions. Negative ions such as halide ions have been found not only to depress the deposition rates to zero, but also to etch the substrates. This latter experiment demonstrates sputtering of the anode by negative ions.