Are the oscillations during the anodic dissolution of Si in dilute fluoride electrolyte damped or sustained?

The current oscillations observed under potentiostatic conditions during the anodic dissolution of silicon in a fluoride electrolyte have been reexamined. This phenomenon, originating from an oscillation of the oxide thickness on the local scale, can be observed as a macroscopic oscillation only if the phase of the local oscillators is synchronized over the whole electrode surface. In the absence of an external excitation, theoretical modeling indicates that such a synchronization can hardly be obtained from a shortrange interaction between the local oscillators. Experimental analysis of the oscillation damping suggests that such an interaction is either absent or extremely weak. We conclude that the synchronization observed in some instances is most plausibly due to global coupling through the uncompensated series resistances of the electrode, its back-contacts, and the electrolyte.