Species transport on the target during high power impulse magnetron sputtering

Abstract

High Power Impulse Magnetron Sputtering (HiPIMS) is a prominent technique to deposit superior materials due to the very energetic growth flux. The origin of this energetic growth flux is believed to be an electric potential structure inside localized ionization zones, the so-called spokes, in the HiPIMS plasma, which rotate in the E × B direction along the racetrack. The measurement of this electric potential or of the electric fields surrounding this ionization zone is extremely challenging due to the very high local power density that obstructs any traditional probe diagnostics. Here, we use a marker technique on the magnetron target to analyze the lateral transport of a target material on a HiPIMS target. We show that the target material is predominantly transported in the E × B direction irrespective of the presence of spokes. However, only when spokes are present, we observe also an enhanced transport in the opposite E × B direction. This is explained by the large electric field at the trailing edges of spokes.

Spokes in high power impulse magnetron sputtering plasmas

“…Due to spoke rotation, some of the atoms or ions might be transported azimuthally by the spoke dynamic and be re-deposited at a distance with respect to the location where they were sputtered at the target surface. Layes et al [45,46] investigated this re-distribution of species using a marker technique: small inserts of Cr were embedded in an Al target at the racetrack position on a circular magnetron and exposed to a HiPIMS plasma. The HiPIMS discharge and the target surface composition were characterised in parallel for low, intermediate and high power conditions, thus covering both the Ar-dominated and the metal-dominated HiPIMS regimes.…”

Kinetic simulation of electron cyclotron resonance assisted gas breakdown in split-biased waveguides for ITER collective Thomson scattering diagnostic

“…25,26 The underlying particle in cell (PIC) code has been used for pure simulation studies [27][28][29] but has also been validated with experiments. [30][31][32] In addition, the code has been validated against the benchmarked reference PIC code yapic. 33,34 By considering an ensemble of pseudoelectrons (each representing a given number of physical electrons) a kinetic description is established.…”

Kinetic simulation of electron cyclotron resonance assisted gas breakdown in split-biased waveguides for ITER collective Thomson scattering diagnostic

“…25,26 The underlying particle in cell particle (PIC) code has been used for pure simulation studies, [27][28][29] but has also been validated with experiments. [30][31][32] In addition, the code has been validated against the benchmarked reference PIC code yapic. 33,34 Simulator electrons are traced in a given 3D geometry based on an unstructured mesh.…”