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.

Zinc gallate (ZnGa₂O₄) thin films were grown on sapphire (0001) substrate using radio frequency (RF) magnetron sputtering. After the thin film deposition process, the grown ZnGa₂O₄ was annealed at a temperature ranging from 500 to 900 °C at atmospheric conditions. The average crystallite size of the grown ZnGa₂O₄ thin films increased from 11.94 to 27.05 nm as the annealing temperature rose from 500 to 900 °C. Excess Ga released from ZnGa₂O₄ during thermal annealing treatment resulted in the appearance of a Ga₂O₃ phase. High-resolution transmission electron microscope image analysis revealed that the preferential crystallographic orientation of the well-arranged, quasi-single-crystalline ZnGa₂O₄ (111) plane lattice fringes were formed after the thermal annealing process. The effect of crystallite sizes and lattice strain on the width of the X-ray diffraction peak of the annealed ZnGa₂O₄ thin films were investigated using Williamson-Hall analysis. The results indicate that the crystalline quality of the deposited ZnGa₂O₄ thin film improved at higher annealing temperatures.

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.

In this study, yttrium fluoride (YF₃) and yttrium oxide (Y₂O₃) coatings were prepared by an atmospheric plasma spraying technique and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). YF₃ powders were sprayed at various plasma spraying powers of 9, 15, and 21 kW. The XRD result indicates that the YF3 coating shows preferred orientations and was well crystallized. The XPS results revealed a strong Y–F bond on the YF₃ coating surface. A porosity value analysis showed that the porosity of the YF₃ coating was lower than that of the Y₂O₃ coating. Moreover, the dielectric strength of the YF₃ coating (22.65 kV/mm) was higher than that of the Y₂O₃ coating (14.42 kV/mm). This confirms that the YF₃ coating exhibits a breakdown voltage of 4.97 kV, which is more than 1.5 times higher than that observed for the Y₂O₃ coating (3.29 kV). These results indicate that the YF₃ coating has better mechanical and dielectric properties than the Y₂O₃ coating, indicating that the YF₃ coating is a very attractive novel antiplasma and corrosion-resistant material.

Yttrium fluoride (YF₃) films were grown on sapphire substrate by a radio frequency magnetron using a commercial ceramic target in a vacuum chamber. The structure, composition, and plasma etching behavior of the films were systematically investigated. The YF₃ film was deposited at a working pressure of 5 mTorr and an RF power of 150 W. The substrate-heating temperature was increased from 400 to 700 °C in increments of 100 °C. High-resolution transmission electron microscopy (HRTEM) and X-ray diffraction results confirmed an orthorhombic YF₃ structure was obtained at a substrate temperature of 700 °C for 2 h. X-ray photoelectron spectroscopy revealed a strongly fluorinated bond (Y–F bond) on the etched surface of the YF₃ films. HRTEM analysis also revealed that the YF₃ films became yttrium-oxyfluorinated after exposure to fluorocarbon plasma. The etching depth was three times lower on YF₃ film than on Al₂O₃ plate. These results showed that the YF₃ films have excellent erosion resistance properties compared to Al₂O₃ plates.