Stability and plasma etching behavior of yttrium-based coatings by air plasma spray process

In recent days, many studies have focused on fluorine-saturated yttrium-based coatings for better material performance in semiconductor processing chambers. In this investigation, yttrium oxide (Y2O3) and yttrium oxyfluoride (YOF) powders were synthesized using a simple solid-state wet chemical process. Then, the Y2O3 and YOF powder feedstocks were coated on an aluminum (Al) substrate using the atmospheric plasma spraying (APS) technique at different plasma powers of 25.6, and 25.2, 33.2 kW, respectively. Microstructure, macroscopic property, and chemical stability of dense Y2O3 and YOF-coated samples were analyzed. The Vickers hardness values of Y2O3 and YOF coated samples were 369.2 +/- 32, and 267.1 +/- 25, 241.9 +/- 31 at plasma powers of 25.6, and 25.2, 33.2 kW, respectively. Y2O3 sample was showed higher hardness value due to less porosity. The etching behavior of the Y2O3 and YOF coatings was analyzed using PECVD-NF3 plasma. X-ray photoelectron spectrum analysis (XPS) has confirmed the fluorination on the etched surfaces. The relative intensity ratios of the Y-F to Y-O peaks on the Y2O3 and YOF coatings after exposure to NF3 plasma were 1.30 and 1.48, respectively. This indicated that the YOF coating showed a strong fluorination layer and superior resistance for fluorine-plasma exposure compared to Y2O3, which is more appropriate for use as a protective material for the inner wall re-actors. Therefore, YOF coated samples have good stability with high erosion resistance, which is highly suggested for applications in the semiconductor industry.