Monitoring Anodic Silicon Dissolution in Acidic Fluoride Electrolyte by the Mirage Effect

Probe beam deflection (PBD) technique was used for the in-situ characterization of p-Si anodic dissolution in fluoride containing acidic media in the regimes of porous Si formation, electropolishing and sustained electrochemical oscillations. When trends in deflectometric signal differed from those of current density, PBD could provide complementary informations on the occurrence of chemical reactions at the electrode. A model is proposed for the estimation of oxide thickness based on the instantaneous formation and dissolution rates in galvanostatic conditions. Results point to the existence of different oxide phases at the p-Si/electrolyte interface.