Wider vision capability provided by a curved surface sample holder for TOF-SIMS imaging

The biggest advantage of time-of-flight secondary ion mass spectrometry (TOF-SIMS) is imaging performance. 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, acquiring accurate images of uniform intensity from three-dimensional (3D) objects having curved surfaces is challenging because the ion extraction field in a TOF-SIMS system is ideally suited for the measurement of flat samples. When the authors observe the samples which have curved surfaces, the observable region is often restricted; it is, therefore, impossible to discuss the chemical abundance of components at various locations on the sample surface. Several methods to solve this problem have been proposed, e.g., delayed extraction or embedding the sample, but each has some disadvantages. Therefore, the authors have developed a curved surface sample holder for the uniform extraction of ions from 3D objects. This sample holder succeeded to expand the observable region dramatically without any significant drawbacks. In this article, the capability for uniform imaging afforded by the newly designed sample holder will be demonstrated.