On the Origin of Electrochemical Oscillations at Silicon Electrodes

Electrochemical oscillations at silicon electrodes anodized in hydrofluoric acid are a well known but poorly understood phenomena. It is less well known that potential oscillations are also observable during anodic oxidation in fluoride‐free electrolytes. In situ measurements of stress, as well as x‐ray reflectometry, atomic force microscopy, and ellipsometry were used to investigate the properties of the thin anodic oxide which covers the electrode surface during the oscillations. The results indicate a transition in the oxide morphology a thickness of about 10 nm. Based on this structural transition a model is developed which explains all observed features of the oscillation process in a consistent way.