Electrical Characterization of the Silicon‐Electrolyte Interface in the Conditions of Porous Silicon Formation

Abstract

A detailed experimental investigation of the electrical behavior of the silicon‐electrolyte interface is presented, which leads to the conclusion that electrochemical dissolution of p‐type silicon (doping range ) during porous silicon formation is mainly determined by the charge exchange at the silicon surface over the Schottky barrier formed at the interface through a thermoionic emission process. Impedance characterization of the interface allows the determination of the potential barrier formed between p‐silicon and hydrofluoric acid solutions, and analysis of I(V) characteristics shows that the silicon‐electrolyte junction behaves like a Schottky diode, with a particular dependence of the anodization potential vs. silicon doping which results from the voltage drop in the Helmholtz layer.