Plasma diagnostics for understanding the plasma–surface interaction in HiPIMS discharges: a review

Abstract

Mass spectrometry of atmospheric pressure plasmas S Große-Kreul, S Hübner, S. Schneider et al. Clusters in intense FLASH pulses C Bostedt, M Adolph, E Eremina et al. Dissociative attachment and vibrational excitation in electron collisions withCl2 M-W Ruf, S Barsotti, M Braun et al. Ionization dynamics of XUV excited clusters: the role of inelastic electron collisions M Müller, L Schroedter, T Oelze et al. Plasma diagnostics for understanding the plasma-surface interaction in HiPIMS discharges: a review Nikolay Britun, Tiberiu Minea, Stephanos Konstantinidis et al.Abstract. Intense laser fields are known to induce strong ionization in atoms. In nanoclusters, ionization is only stronger, resulting in very high charge densities that lead to Coulomb explosion and emission of accelerated highly charged ions. In such a strongly ionized system, it is neither conceivable nor intuitive that energetic negative ions can originate. Here we demonstrate that in a dense cluster ensemble, where atomic species of positive electron affinity are used, it is indeed possible to generate negative ions with energy and ion yield approaching that of positive ions. It is shown that the process behind such a strong charge reduction is extraneous to the ionization dynamics of single clusters within the focal volume. Normal and well-known charge transfer reactions are insufficient to explain the observations. Our analysis reveals the formation of a manifold of Rydberg excited clusters around the focal volume that facilitate orders of magnitudes more efficient electron transfer. This phenomenon, which involves an active role of laser-heated electrons, comprehensively explains the formation of copious accelerated negative ions from the nano-cluster plasma.

The Target Material Influence on the Current Pulse during High Power Pulsed Magnetron Sputtering

“…The main reason is the rarefaction of the working gas due to momentum transfer between the sputtered atoms, and working gas atoms. This reasoning is substantiated by experimental evidences based on different plasma diagnostic techniques [32]. However, modeling also indicates there is an alternative mechanism for gas rarefaction, i.e.…”

Towards smart electrolytic plasma technologies: An overview of methodological approaches to process modelling

“…Relationships among different EPPs discussed in [1] form a phenomenological basis for EPHT, PEO and other processes. A phenomenological model of coating stripping [78] can also be used to understand 12 various EPPs. Microdischarge evolution in the pores of oxide layers and oxide crystallisation phenomena during PEO processes have been discussed in [79][80][81].…”

“…It is not surprising to see smart elements, such as active plasma diagnostics and variable process parameters, in recent developments of plasma-based surface engineering technologies, e.g. PE-CVD [9,10] 5 and Hi-PIMS [11,12]; for EPPs however this still remains in a rudimentary state despite some recent progress [13].…”

Influence of ionisation zone motion in high power impulse magnetron sputtering on angular ion flux and NbOxfilm growth

“…HiPIMS is typically characterised by high discharge peak currents and a high degree of ionisation of the sputtered species enabling energetic growth conditions with enhanced control possibilities during film deposition. The method has been reviewed several times and further details can be found in the following reviews: Helmersson et al [2], Sarakinos et al [3], Gudmundsson et al [4] and Britun et al [5].…”