| AVS 64th International Symposium & Exhibition | |
| Surface Science Division | Tuesday Sessions |
| Session SS-TuP |
| Session: | Surface Science Poster Session |
| Presenter: | Yoshinobu Shiba, Tohoku university, Japan |
| Authors: | Y. Shiba, Tohoku university, Japan A. Teramoto, Tohoku university, Japan T. Goto, Tohoku university, Japan Y. Kishi, Nippon Yttrium Co., Ltd, Japan Y. Shirai, Tohoku university, Japan S. Sugawa, Tohoku university, Japan |
| Correspondent: | Click to Email |
Chemically stable materials that have corrosion resistance from reactive species enhanced by plasma have been required for an inner wall of semiconductor process chambers. Although the materials with low formation enthalpy (such as aluminum oxide (Al2O3) and yttrium oxide (Y2O3)) have been widely used for the protect material, it was revealed that yttrium oxyfluoride (YOF) was much stable than Y2O3 against the reactive species. [1] In this research, we compared the chemical stability of Yttrium trifluoride (YF3) and that of YOF. The enthalpy of formation of YF3 (-1719 kJ/mol) is close to Y2O3’s (-1905 kJ/mol), and the enthalpy of formation of one metal-fluorine bond of YF3 (-573 kJ/mol) is smaller than that of one metal-oxygen bond of Y2O3 (318 kJ/mol). YF3 films and YOF films were exposed to N2/Ar, H2/Ar, NH3/Ar, NF3/Ar, and O2/Ar plasmas using microwave-excited surface-wave high-density plasma equipment [2], and investigated their corrosion resistance. After plasma-irradiation, the YF3 film's surfaces were damaged, and the fluorine content in YF3 decreased in all condition. In contrast, the YOF’s surfaces were not changed by these plasmas. These indicate that the YOF is much stable against the plasma bombardment than the YF3.
[1] Shiba et al. J. Vac. Sci. Technol. A 35, 021405 (2017)
[2] T. Ohmi, et al. J. Phys. D: Appl. Phys., 39, R1 (2006)