CU DEPOSITION ONTO N-GAAS(100) - OPTICAL AND CURRENT TRANSIENT STUDIES

The deposition of Cu from sulphuric and hydrochloric acid solutions on to n-GaAs(100) has been studied by a combination of electrochemical an d optical techniques. Reflectance-potential curves allowed Cu depositi on and dissolution to be monitored in the presence of side reactions w hich, particularly in chloride-containing electrolytes, mask the depos ition process in the cyclic voltammograms. Nucleation and growth of th e Cu clusters on n-GaAs(100) has also been investigated by potential s tep experiments and the resulting current transients analyzed in terms of standard nucleation models. Cu was found to deposit via progressiv e nucleation, even onto GaAs surfaces which were covered by a rutheniu m adlayer. The nucleation rate for the Ru-modified surface was clearly lower than for bare n-GaAs(100).