Kinetics and Mechanism of the Etching of CoSi2 in HF‐based Solutions

The wet etching behavior of CoSi 2 films in HF‐based solutions is investigated for a wide range of experimental conditions. It is established that the etching rate of CoSi 2 depends on the concentrations of H + ions and on the initial concentration of HF ( [ HF ] i ) . Interaction of H + and HF with the CoSi 2 occurs in the adsorption layer. The concentration of adsorbed particles is described by the equation of the Freundlich adsorption isotherm. The kinetic equation of the etching rate is R = k R Θ H + Θ HF , where k R ≈ 2.5 ⋅ 10 7 exp (−10500/ RT ) nm/s (0.416 at 293 K), Θ H + ≈ [ H + ] 0.135 and Θ HF ≈ [ HF ] i 0.310 . It is shown that the induction period increases in the etching process of CoSi 2 in diluted HF, which is attributed to the presence of a thin surface layer on top of the CoSi 2 .