Residual stress control in MoCr thin films deposited by ionized magnetron sputtering

This study reports on the control of intrinsic stress in MoCr films deposited by ionized magnetron sputtering using a secondary plasma created through a radio-frequency (13.56 MHz) antenna.The efficiency of the additional antenna has been investigated by optical emission spectroscopy for a MoCr target. It appears that ionization of the sputtered species is significantly enhanced compared to a conventional magnetron sputtering. Moreover, by controlling the substrate bias, the RF power on the antenna and the discharge gas pressure (argon), the ion energy and flux can be strongly modified. Therefore, we have the ability to act on composition, growth rate, microstructure and residual stress of the deposited film. Indeed, the films exhibit residual stress varying from compressive value (− 3.4 GPa) to tensile one (1.7 GPa). In particular, only by varying the RF power on the antenna, a wide range of tensile and compressive stress can be obtained without affecting the chemical composition of the films. These results will be useful when elaborating stress-engineered micro-objects such as micro-springs.