Stress and magnetoelastic properties control of amorphous Fe80B20 thin films during sputtering deposition

In situ stress measurements during sputtering deposition of amorphous Fe80B20 films are used to control their stress and magnetoelastic properties. The substrate curvature induced by the deposited film is measured optically during growth and quantitatively related to the deposition induced accumulated stress. The resulting magnetic properties are later correlated with the measured stress for a wide range of sputtering pressures [(2-25)x10(-3) mbar]. A significant tensile stress develops at the film-substrate interface during the early growth stages (initial 2-3 nm). At a critical thickness, a transition is observed from tensile to compressive stress, which is associated with amorphous island coalescence. By further increasing the thickness, a compressive stress follows, which is related to the local distortion induced by the ion peening effect. The Monte Carlo simulations of the sputtering process describe quantitatively the experimental results as a function of the Ar pressure and target bias voltage. (C) 2008 American Institute of Physics.