Gold Metallization of Silicon by Galvanic Displacement

There are several microelectronic processes which are based on gold due to its unique physical and chemical properties. Adhesion of gold films which are deposited by galvanic displacement is investigated by microindentation measurements. For investigation, load-displacement tests are performed on gold nanostructures which are deposited onto mono (100) and polycrystalline silicon in sulfite solutions. Composite hardness model for soft film on hard substrate is used to analyze the results. Gold films growth and composite Vickers microhardness are influenced by the adhesion of the gold film to silicon, as a function of different electrolytes and silicon substrates. The higher composite hardness and more extended deformation zone at the film/substrate lead to stronger adhesion. For the same film thickness, the composite hardness of films which are deposited onto mono silicon is higher than films on poly silicon. The effect of cysteine as additive on adhesion and microhardness measurements is emphasized.