Surface roughness effect on Mo physical sputtering and re-deposition in the linear plasma device PSI-2 predicted by ERO2.0

•The effect of the surface roughness was implemented in the 3D Monte-Carlo code ERO2.0 to investigate the surface shape influence on sputtering parameters (average sputtering yield, angular and energy distributions of sputtered particles, their re-deposition) and conduct predictive modelling of planned molybdenum (Mo) surface roughness experiments at the linear plasma device PSI-2.•Various types of generic rough surfaces (regular cosine peaks and irregular randomly formed surface defined by a given fractal dimension Dfract) were implemented in the ERO2.0 code and used as test cases. Accounting for the non-uniform azimuthal distribution of sputtered particles in case of the oblique incidence of plasma ions was implemented and has shown to decrease the resulting effective sputtering yield. Time evolution of the surface topography under the plasma irradiation was incorporated.•Considered roughness types lead to the decrease of erosion and collimation of the resulting angular distribution of Mo atoms escaping the surface. For regular cosine peaks, the effective sputtering yield decreases by a factor of 6 with the increase of the surface structures’ aspect ratio from 0.1 to 3.0 and by up to the factor of 4 for irregular structures of the surface fractal dimensionality from dfract = 2.01 to dfract = 2.90. Preferential sputtering of the “hills” and target material re-deposition in the “valleys” lead to the flattening of the surface.