Correlation between surface non-radiative recombination and current oscillation at p-Si(100) during electropolishing in fluoride solution

The electropolishing of p-Si(100) in aqueous NH4F solution is investigated in-situ by photoluminescence (PL) with short N-2-laser pulses. The PL signal increases with potential and reaches a maximum when current oscillations occur. The PL signal oscillates with the same period but anticorrelated to the current. The thin anodic oxides are removed at a low cathodic potential. The respective peak of the current transient is used to monitor the relative changes of the anodic oxides. The results are discussed from the point of view of non-radiative defect generation during electropolishing, which is controlled by the potential and the rate of oxidation.