The Anodic Dissolution of Silicon in HF Solutions

Abstract

The impedance response of n, p−, n+, and p+ silicon was studied during dissolution and electropolishing in HF solutions. Characteristic capacitive and inductive impedances were seen as a function of potential and dopant concentration. For the n+ and p+ silicon, the electrode response was dominated by the potential drop across the Helmholtz layer and, at higher potentials, to the response of the oxide layer. Characteristic impedance responses were associated with Tafel dissolution and oxide formation. For the p− silicon close to the open‐circuit potential, an additional contribution to the impedance response was seen from the space‐charge layer. For the n silicon the impedance response was dominated by the potential drop across the space‐charge layer.