Stress evolution in CoxFe1−x (x = 0.33–0.87) electrodeposited films

Electrodeposition of 0.5 μm thick CoxFe1−x (x = 0.33–0.87) films was carried out from a sulfate/chloride plating solution containing saccharin as an organic additive at constant current density and a controlled pH 2.3. The increase of Fe2+ concentrations in plating solution resulted in an increase of Fe-content and tensile stress in CoxFe1−x films, which is accompanied by a decrease of plating rate. Several possible origins for generation of tensile stress include the following: interfacial stress between CoFe films and Cu-substrate, crystal texture and grain size, coalescence and stress evolution during film growth, and hydrogen adsorption/desorption. The adsorption/desorption mechanism of hydrogen seems to be the most likely dominant stress mechanism. The relationship between increase of the tensile stress and decrease of plating rate was discussed.