KINETICS OF COOPER PHOTOELECTROCHEMICAL DEPOSITION ON SILICON

Resumo

This work investigates the kinetics mechanism of photoelectrochemical deposition of copper on p-silicon. The cooper thin film was obtained by a copper sulfate solution under HeNe laser illumination. Using the law of potential sweep rate dependence with the current density peak, for the reaction reduction Cu²⁺ + 2 e^- = Cu, by several light power densities, the controlling mechanism of this reaction was determined. The kinetics mechanism depends on the flux of photocarriers with the potential sweep rate. It was observed that the mechanism could be controlled by electron hole generation; in this case, the film obtained is dense and uniform. The kinetic equation for the photodeposition process was determined. The photodeposition reaction rate decreases linearly with the deposition time. The following equation describes the growth rate dependence with reaction time for a specific laser power: r = (0.051±0.002) – (4.4±0.2) x10^-4t.