In this work we present a theoretical model that explains the current and voltage oscillations at the Si electrode in HF media. A simulation computer program based on this model is implemented and results are shown. Oscillations of the current and (for the first time) the voltage obtained numerically fit perfectly with experiments. The model allows to obtain more information about the system in the form of maps (accompanied by histograms) of e.g.: oxide thickness distribution, SiO2/HF and Si/SiO2 interfaces morphology, or local voltage losses. Other characteristics of the oxide like capacitance or roughness can also be obtained.