Investigations on high power impulse magnetron sputtering by optical emission spectroscopy of NiCr in different compositions (40/60 and 80/20)

In many technical applications additional information about the resulting loading or actually applied forces are gained by the use of strain gauges. Besides polymer based strain gauges which are glued to the surface improved signal quality is gained by use of directly sputterd strain gauges, avoiding creeping and swelling due to temperature and humidity. For improved properties, like thermal stability and adhesion, High Power Impulse Magnetron Sputtering (HiPIMS) is used. Due to the increased degree of ionization of the target material by HiPIMS also the resulting film for properties e.g. the film structure can be modified by process parameters like voltage, current, duty cycle,or pulse oackages. Actually investigations using only single pulses are reported. Besides the use of single pulses this paper also discusses the influence of pulse packages, i.e. several single pulses in short sequence followed by a long off-time. Modifications of the electrical fingerprint of the processes (current, voltage behaviour) and the plasma emission, measured by time resolved optical emission spectroscopy (OES) will be presented for two NiCr targets with different stoichiometry. It turned out that the optical intensity of the ionized material is direct proportional to the induced power.