Calorimetric investigations in a gas aggregation source

A gas aggregation source based on DC magnetron sputtering was investigated using a passive thermal probe and supplementary diagnostics (Langmuir probe and quartz crystal microbalance). Parameter variations of pressure, axial distance, and magnetron current have been performed for three different targets (pure Cu, pure W, composite Cu/W) in argon discharge. The measurements showed the energy flux to be significantly higher for the case of the pure tungsten and the composite target compared to the copper target, which is likely a result of the strongly increased amount of neutrals being reflected from the heavier targets. Furthermore, gas rarefaction by the sputtered atoms was found to be essential for the understanding of the observed energy flux and that the dominant contributors to the energy flux in the higher pressure regime are comparable to those observed in the conventional lower pressure regime. Selected deposited films have been investigated ex-situ by scanning electron microscopy, which allowed us to gain insight into the nanoparticle formation in relation to the observed energy conversion.