The angular distribution of secondary ions is one of the essential elements for development of three-dimensional (3D) shave-off SIMS. The magnification lens system in the 3D shave-off SIMS was designed and assembled based on the detection position of the detector. However, shave-off condition of high incidence energy (30 keV) and angle of incidence (87 degrees), we simulated the angular distribution of sputtered particles using the SDTrimSP program and compared the results with the previous shave-off experimental data. Even unusual the shave-off beam, the SDTrimSP simulation results showed a good agreement and a similar tendency with the experimental data. SDTrimSP simulation is expected to be useful in obtaining the sputtered particle information for development and instrumentation of 3D shave-off SIMS.

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Secondary ion mass spectrometry (SIMS) has some disadvantages including degradation in depth resolution depending on the depth which are difficult to resolve. To address these disadvantages, we have previously developed shave-off SIMS and achieved two-dimensional mapping. In this study, we designed the appropriate secondary ion optical system by simulation to achieve three-dimensional shave-off SIMS. We developed new optical parts and evaluated the abilities of the designed secondary ion optical system. We acquired the following abilities of the secondary ion optical system: magnification ratio 1.6 × 10², Z-axial resolution 0.70 □m, and transmission > 0.1%.

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The biggest advantage of TOF-SIMS is imaging capability. TOF-SIMS is the only surface analysis technique which can provide the elemental and molecular ion images with high spatial resolution and high sensitivity. However, it is difficult to deal with topographic samples such as wire or sphere, because TOF-SIMS is designed to do a spectrum and image analysis with flat samples. The observable region in wire and sphere samples was restricted, then it was impossible to discuss the accurate distributions of specific ions on the sample surface. Several methods to solve this problem have been proposed, but they had some disadvantages. Therefore, the authors have developed newly designed sample holder for the samples which have curved surface. The authors succeeded to expand the observable region dramatically without any significant drawbacks. In this article, the details of curved surface sample holder and its evaluation results will be discussed, and applications using this sample holder are also discussed.

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We have investigated the Auger depth profiling analysis of HfO₂/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 HfO₂ 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 HfO₂ 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 HfO₂/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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