Secondary ion mass spectrometry can analyze all elements and has high versatility. In our laboratory, we have established a method of sputtering the whole sample from the side by using partial primary beam called Shave-off method, which increases spatial resolution and eliminates an effect originated by surface roughness. Furthermore, designing the ion optics that can enlarge and converge the emitted secondary ions from the cross section of the micro sample on the detector, high-precision three-dimensional distribution data with surface resolution of several nanometer level and depth direction resolution of several tens of nanometer level can be obtained at high speed. However, the secondary ions trajectory and the ion aberration caused by the lens in the Shave-off condition have not been verified. In this study, we have constructed a simulation of calculating the trajectory of emitted ions from the Shave-off cross section. It is expected that the simulation will be of great help and powerful tool for future development.

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 × 10 2 , Z-axial resolution 0.70 m, and transmission > 0.1%.

Shave-off method has been proven its efficacy for highly precise depth profiling in secondary ion mass spectrometry (SIMS) analysis. The unique technique, shave-off method has distinctive cross-sectional shape after scanning compared with raster scan method. We investigated the cross sectional shape of three different height tungsten samples using focused ion beam scanning electron microscopes (FIB-SEM) and transmission electron microscope (TEM). Though it is a simple cross-sectional shape, the analysis results enable the investigation of an angle between primary ion beam and sample surface, and sputtering yield.

The concept of three-dimensional (3D) shave-off secondary ion mass spectrometry (SIMS) is that enables to obtain the depth information of the sample simultaneously with the mass information using the vertical axis of a two-dimensional position-sensitive detector in the mass analyzer. In this study, we simulated the trajectory of secondary ions sputtered from a virtual sample in the 3D shave-off SIMS system and investigated the magnification ratio of the ions. The simulation results showed that we could distinguish the depth position of the secondary ions sputtered from a sample by the detected position in our concept of 3D shave-off SIMS.