Yttrium fluoride (YF₃) and yttrium oxide (Y₂O₃) protective coatings prepared using an atmospheric plasma spraying technique were used to investigate the relationship between surface erosion behaviors and their nanoparticle generation under high-density plasma (10¹²–10¹³ cm⁻³) etching. As examined by transmission electron microscopy, the Y₂O₃ and YF₃ coatings become oxyfluorinated after exposure to the plasma, wherein the yttrium oxyfluoride film formation was observed on the surface with a thickness of 5.2 and 6.8 nm, respectively. The difference in the oxyfluorination of Y₂O₃ and YF₃ coatings could be attributed to Y–F and Y–O bonding energies. X-ray photoelectron spectroscopy analyses revealed that a strongly fluorinated bonding (Y–F bond) was obtained on the etched surface of the YF₃ coating. Scanning electron microscopy and energy dispersive X-ray diffraction analysis revealed that the nanoparticles on the 12-inch wafer are composed of etchant gases and Y₂O₃. These results indicate that the YF₃ coating is a more erosion-resistant material, resulting in fewer contamination particles compared with the Y₂O₃ coating.

This study investigates the microstructure, mechanical and electrical properties of dense yttrium oxyfluoride (YOF) coatings fabricated by the atmospheric plasma spraying technique. Transmission electron microscopy and X-ray diffraction analysis revealed a well crystallized YOF coating with preferred orientations. The YOF coatings were more porous (approximate porosity 0.5%), with higher hardness (290 ± 30 HV), lower electrical resistivity (10¹⁶ Ω⋅cm), and breakdown voltage (5.57 kV), than conventional yttrium-fluoride plasma-protective coating. These results indicate the potential of the YOF coating as a novel antiplasma and corrosion-resistant ceramic.