Novel Linkage Technology of the Shared Alignment Sample Holder for Same Area Observations with Electron Microscopy and Scanning Probe Microscopy

Abstract

We developed an innovative air protection sample holder enabling a hermeneutically sealed sample transfer from Hitachi's ion milling instrument to the Field Emission Scanning Electron Microscopes (FE‐SEM) and the environment control high‐vacuum Scanning Probe Microscope (SPM) AFM5300E for a correlative microscopy (Figure 1). In a previous study, we explained the advantages of this sample holder with regard to the analysis of cathode materials in a lithium‐ion battery [1]. Our novel SEM‐SPM linkage system with the shared alignment sample holder enables a software‐based alignment of the same measurement area for a comprehensive analysis of sample surfaces with Hitachi's FE‐SEM SU8200 Series and the new midsize‐sample SPM AFM5500M, characterized by the automation of the cantilever exchange, laser alignment, feedback parameter tuning and data processing (Figure 2). As the XY‐stage of both microscopes drives with high accuracy to the desired area by only registering three specified coordinates of the sample stage, this linkage system facilitates a correlative microscopy of samples that are difficult to align optically. In this study, we used this technology to analyse a multilayer graphene on a SiO 2 substrate. For an observation of graphene, FE‐SEM is one method to explain the relationship between SE contrasts and the thickness of graphene layers. Another method is the Kelvin force microscopy (KFM) explaining the quantitative relationship between surface potentials and topographic heights. Thus, a linkage of both observation methods enables a correlative analysis of SE contrasts, topography and surface potentials. Figure 3 shows the SE image obtained at a accelerating voltage of 0.5 kV, topography and the KFM image of a multilayer graphene on a SiO 2 substrate measured with the linkage system. The grey island structure with two different contrasts and several lines in the SE image are well aligned with the topography and KFM images. Analysing the topography, we confirmed that SE contrast differences result from single graphene step heights. Furthermore, we have learned that the surface potential of a bilayer graphene is 15–20 mV higher than that of a monolayer graphene. In conclusion, the linkage system is a tool for a comprehensive analysis of a sample's composition, structure, 3D topography, mechanic and electro‐magnetic properties with the SEM and SPM instruments without any constraints in regard to their performances.