We have investigated the Auger depth profiling analysis of HfO
2/Si by the glancing-angle ion beam sputtering method at an incident angle of 7 degree from the sample surface with argon ion beam. The depth resolutions of the O KLL interface profiles were 0.9 nm and 1.5 nm, at the ion-beam acceleration voltage of 2.0 kV and 3.0 kV respectively, which were better than the depth resolutions at a commonly-used incident angle of 51 degree. However, the ion-beam-induced reduction of HfO
2 was not suppressed by the glancing-angle ion beam sputtering at the ion acceleration voltage of 0.5 kV, which is expected to be the lowest damage sputtering condition in this study. The reduction of HfO
2 due to preferential sputtering of oxygen was observed by the intensity ratio of O KLL and Hf NVV depth profiles. It was found that the ratio of preferential sputtering depends on the ion incidence angle and the ion acceleration voltage. Under the glancing-angle condition, the ratio of preferential sputtering greatly depended on the ion accelerating voltage, and it was found that the lower the ion acceleration voltage is, the easier it is for O to be sputtered than Hf. On the other hand, under the commonly-used incident angle conditions, the ratio of preferential sputtering did not depend much on the ion acceleration voltage. The dependency of the ratio of preferential sputtering on the ion incidence angle can be explained by the difference in sputtering models depending on the ion incidence angle. It was found that the O KLL depth profiles showed partial recovery of the oxygen intensity near the interface of HfO
2/Si, which can be related to oxygen generated by the ion-beam-induced decomposition of the diffusion layer at the interface. In addition, the glancing-angle ion beam enables the reduction of the effect of recoil implantation of Hf atoms into the Si substrate.
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