RF models for plasma-surface interactions: Sheath boundary conditions with dielectrics

Computational models for DC and oscillatory (RF-driven) sheath potentials, arising at metal or dielectric-coated surfaces in contact with plasma, are developed from first principles using particle-in-cell modeling in the VSim FDTD code. These results are used to formulate lumped-element boundary conditions¹, applicable in both fluid² and particle VSim modeling scenarios, wherein sub-grid models for sheaths or dielectric-modified sheaths retain self-consistency in modeling salient physical properties (e.g. sheath-modified particle and heat fluxes) at material surfaces. In this manner, sheath potentials, EEDF evolution, and sputtering physics associated with sheath formation can be included in macroscopic simulations which need not resolve the spatial scales of the sheath explicitly.