Modelling of tungsten sputtering by argon particle bombardment on a fuzzy surface

The physical sputtering yield of a tungsten (W) fuzzy surface by argon (Ar) plasma bombardment was measured in the linear plasma device PISCES-B, which showed an evident reduction in the physical sputtering yield on the fuzzy surfaces in comparison with a smooth surface (Nishijima D. et al 2011 J. Nucl. Mater. 415 S96). In order to reproduce and explain this phenomenon, dedicated modelling of W physical sputtering on smooth and fuzzy surfaces by Ar bombardment has been performed with the three-dimensional kinetic Monte Carlo code SUROFUZZ. According to a measured porosity distribution, W fuzzy surface morphology is constructed in our simulation, on which physical sputtering, trapping and escaping of W atoms under Ar bombardment are simulated with SURO-FUZZ. Detailed comparison between simulation and experiment reveals that microscopic structures of W fuzzy nanofibers play a critical role in the trapping of W atoms and hence in the resulting physical sputtering yield. For the same porosity distribution, the simulated physical sputtering yields of W fuzzy surface morphology with shallow valleys are higher than the measured values, while W fuzzy surface structure with deep and narrow slots results in a lower physical sputtering yield compared to the experimental data. The good agreement between simulation and experiment can be attained for W fuzzy surface morphology with deep and relatively open recessions.

Automated summary

The study demonstrates the critical role of microscopic structures of tungsten fuzzy nanofibers in physical sputtering, with deeper and relatively open recessions leading to a better agreement between simulation and experiment data.