Anodic Dissolution of Si: Electrochemical Oscillations and Porous Silica Formation

The behavior of a silicon electrode in fluoride electrolyte is reviewed. Special attention is directed to the electrochemical oscillations observed in the 3-10 V potential range, and to the formation of a mesoporous silica film above 10 V. The oscillatory phenomenon is shown to survive in this high-potential range. The physical mechanisms at the origin of the oscillation are discussed, in light of the various models proposed (stress-induced breakdown vs dielectric breakdown). The model of local oscillators appears as yet as the most suitable one to describe the transition from a resonant behavior to a macroscopic oscillation. Some directions for solving the pending issues are proposed.