Dynamic features of the electron drift and electron properties in a HiPIMS discharge

Abstract

Abstract Information on the evolution of electron properties during high-power impulse magnetron sputtering (HiPIMS) operation of planar magnetrons enables the study of fundamental physical processes. In this work, incoherent Thomson scattering is implemented for the non-invasive, spatiotemporally-resolved characterization of electron properties and drifts in the HiPIMS regime of a planar magnetron. In the ionization region of argon and helium plasmas, the azimuthal electron drifts are directly measured perpendicular to the magnetic field and are found to evolve according to a changing balance of E × B and diamagnetic electron drifts, while radial electron drifts, measured parallel to the magnetic field, can be attributed to plasma expansion/contraction and centrifugal forces. The evolutions of electron density and temperature in the afterglow plasma phase show the existence of two time scales for the variation of plasma properties. These characterizations provide detailed information on electron properties and dynamics in regions of the magnetic trap ordinarily inaccessible to invasive diagnostics.