In situ X-ray analysis of solid/electrolyte interfaces: electrodeposition of Cu and Co on Si(111):H and GaAs(001) and corrosion of Cu3Au(111)

Metal deposition is of major importance in the semiconductor industry. The electrochemical growth of metals is attracting increasing attention because the adjustment of the electrochemical potential via the electrode potential offers a unique way of controlling growth and structure of the interface. However, the fundamental aspects of the growth process are not well understood. The electrochemical corrosion processes are, of course, of major economic importance. Electrochemical deposition of Cu and Co in monolayer amounts on hydrogen terminated Si(111) was studied ex situ and in situ by X-ray techniques. The X-ray beam was found to have a strong effect on the deposit causing desorption under the beam. Cu deposition on GaAs(001) from UHV is compared with electrodeposited Cu on the same surface, elucidating similarities and differences of electrochemical and UHV deposition. Roughening due to corrosion of Cu3Au(111) is observed by crystal truncation scattering. The observed behaviour of passivation of this surface is explained by the formation of Au clusters, increasingly covering the surface at higher oxidation potential.