Fluorine and oxygen plasma exposure behavior of yttrium oxyfluoride ceramics

Yttrium oxyfluoride ceramics, YOF and Y5O4F7, are promising materials with plasma durability and they are expected to be suitable for plasma etching equipment. In this study, high energy fluorocarbon and oxygen plasma exposure behavior of YOF and Y5O4F7 was evaluated. Due to simultaneous sputtering and chemical reaction, etching rates depended not on materials but on plasma conditions. Surfaces of Y2O3, YOF and Y5O4F7 showed crater-like patterns after exposure to high-energy plasmas. Morphological observation and line roughness evaluation showed good durability of Y5O4F7 because it had a flatter surface than YOF and Y2O3 after plasma irradiation. TEM cross-sectional observation confirmed a disordered lattice pattern on Y2O3 and YOF after fluorocarbon plasma and oxygen plasma exposure.