ON THE ORIGIN OF ELECTROCHEMICAL OSCILLATIONS AT SILICON ELECTRODES

Electrochemical oscillations at silicon electrodes anodized in hydrofl uoric acid are a well known but poorly understood phenomena. It is les s well known that potential oscillations are also observable during an odic oxidation in fluoride-free electrolytes. In situ measurements of stress, as well as x-ray reflectometry, atomic force microscopy, and e llipsometry used to investigate the properties of the thin anodic oxid e which covers the electrode surface:during the oscillations. The resu lts 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 consis tent way.