Properties of Nichrome sputtered by HIPIMS in unipolar and DC-superimposed mode

Nichrome(Ni-Cr) alloys are a common used material for strain gauges. Using High Power Impulse Magnetron Sputtering (HIPIMS) the properties of the film are modified compared to dc-sputtering. In this paper the modifications of the film structure using unipolar and dc-superimposed HIPIMS will be discussed. The change in crystal size depending on the preparation conditions was investigated by X-ray Diffraction (XRD). A slight increase in density was found for the pulsed processes, measured by X-ray Reflectivity (XRR). For commercial cathodes it was found that the current was saturated at approximetely 80 A for pulsing. With a redesign of the cathodes with increased magnetic field the impedance was lowered and the current, i.e. the pulse power could be increased significantly. Also first results with the modified cathodes will be presented.