Bias voltage dependent electrochemical impedance spectroscopy of p- and n-type silicon substrates

In the second series, the analysis of the impedance diagrams was focused on the range of potentials corresponding to the onset of an accumulation layer within the semiconductor. In the case of p-Si, this condition corresponds to the rapid anodic etching of the silicon substrate. At a particular value of the bias, an important induction loop was observed in addition to the usual capacitive behaviour. A Fourier transform treatment demonstrated that the impedance components were interrelated to the time dependent current response under constant bias potential. Then, simultaneous experiments based on chronoamperometry measurements suggested that the electrochemical processes involved in the reaction of Si substrate with HF solution was correlated to a two-step charge transfer mechanism. This interpretation is valid for both the inductive loop obtained in electrochemical impedance spectroscopy and the rise of current versus time observed in chronoamperometry.