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2018
Conference Paper
Titel
Controlling stoichiometry and ionization of reactive HIPIMS processes by using plasma emission monitoring
Abstract
In recent years, the focus of research in High Power Impulse Magnetron Sputtering (HIPIMS) has shifted to reactive processes. In contrast to the often-referred reduction in deposition rate by metallic HIPIMS, there are several publications indicating that for reactive HIPIMS similar or even higher deposition rates for films with superior properties are possible. Despite a reduced hysteresis effect in the case of reactive HIPIMS, this process still has to be controlled regarding stoichiometry and ionization for achieving high film qualities, especially on larger scale. While monitoring the reduction of the intensity of a characteristic metal emission line is well established in conventional DC and MF sputtering, the question arises which effects contribute to the reduction of the emission intensity and how valid these information s are for a defined process control in HIPIMS. Using plasma monitoring and titanium as a well studied model material the correlation of optical emission and the measured intensity of neutral and ionized species was studied for reactive HIPIMS processes. Based on these findings an active optical control is shown, that allows for adjusting the working point, i.e. reactive gas flow and the ionization independently. For example, high values for transparency and refractive index are indicators of a correct stoichiometry ratio and good crystallinity due to a high degree of ionization. Additionally the resulting film properties will be discussed for different working points.