Kinetic studies on electrochemical stripping of CrN films

Chromium nitride (CrN) films deposited on silicon substrates by a cathodic arc plasma technique were electrochemically stripped off in KOH alkaline electrolytes. Current densities and electrolyte concentrations were varied to investigate their influences on the stripping process. By analyzing the relation between the potential and reaction time, it is possible to determine the optimal time for terminating the stripping process because of the different resistivities of the substrates and overlayers. The critical stripping times were defined from the potential−time relation and were observed to be inversely proportional to the current density. The total required charge/unit volume was also determined. The relationship between the thickness of the residual films after stripping and the reaction time at various current densities and KOH concentrations was analyzed using a kinetic model. Moreover, CrN films deposited by another method, namely, unbalanced magnetron sputtering, were also tested for comparison. The stripping process was apparently influenced by the microstructure of the films.