Effects of Charging and Crystallinity on Sputter-Etching Rate of Al2O3 Single Crystal

In this study, we examined Ar+ ion sputter etching rate ratio RAl203/RSiO2 under different surface charging conditions and in different incident azimuthal directions of Ar+ ion. When the surface charging of specimen was neutralized by irradiation with low-energy electrons, RAl2O3 became larger than that of specimens without any electron irradiation at same ion current density. When the specimen was bombarded by Ar+ ion from the azimuthal direction parallel to the a-axis on the surface of Al2O3 single crystal, RAl2O3/RSiO2 became higher than that of specimen bombarded from the azimuthal direction vertical to the a-axis. The effects of surface charging and incident azimuthal direction of Ar+ ion on RAl2O3/RSiO2 are discussed respectively on the basis of the experimental results.