Drift-driven microturbulence in planar magnetrons

E x B discharges play a well-known role in plasma-assisted deposition. Planar magnetrons operated in high-current, pulsed regimes are used for tailored thin film deposition with improved properties. In spite of this, an understanding of the physics of such regimes and how to model their particle dynamics is still far from complete. As with other E x B discharges, in addition to large-scale self-organization [1], the presence of microinstabilities has been demonstrated [2], with implications for performance and modeling. Coherent Thomson scattering studies of electron density fluctuations reveal a rapid evolution in amplitude and frequency of the azimuthal electron cyclotron drift instability during pulsing. Counterpropagating ion-ion two-stream instabilities, in the presence of a complex electric field structure and multiple ionization states, are also created. 2D PIC MCC simulations [3] also reveal modulations in the electron density consistent with short-scale wave activity. These recent findings on magnetron microturbulence are discussed.

[1] J-P. Boeuf and M. Takahashi, Phys. Rev. Lett. 124, 185005 (2020)

[2] S. Tsikata and T. Minea, Phys. Rev. Lett. 114, 185001 (2015)

[3] A. Revel, T. Minea and C. Costin, Plasma Sources Sci. Technol. 27, 105009 (2018)