Electrodeposition of thin films and multilayers on silicon

Cu, Co and Ni thin films and Co-Ni-Cu/Cu multilayers have been electrodepos ited directly on n-type silicon substrates. This removes the need of using a seed-layer deposited by some other methods as a part of the growth proces s and integrates an efficient, inexpensive and convenient method for fabric ating thin films with silicon technology. The deposits were prepared under potentiostatic conditions from different aqueous solutions, containing basi cally: (i) sulphates of the metallic ions plus sodium sulphate and boric ac id for thin films and (ii) Ni sulphamate, Co sulphate, Cu sulphate, boric a cid and sulphamic acid for multilayers. Aspects related to the deposition p rocess and deposited layers were investigated by cyclic voltammetry, curren t transients, scanning electron microscopy, Rutherford backscattering and m agnetoresistance measurements. Typically, thin compact metallic layers with regular granularity were obtained. Depending on the additives used, differ ent nucleation and growth mechanisms were observed. Magnetic multilayers wi th a maximum giant magnetoresistive (GMR) ratio of about 10% were produced.