Two Microscopes Are Better Than One – A Unique New Inspection Tool For Advanced Characterization by In Situ Combination of AFM and SEM

Combining different analytical methods into one instrument is of great importance for the simultaneous acquisition of complementary information. Especially the in-situ combination of two of the most powerful microscopy techniques – scanning electron microscopy (SEM) and atomic force microscopy (AFM) – enables completely new insights in the micro and nano-world. [1,2] In this work, we present a unique inspection tool that seamlessly combines SEM and AFM for inspection and process control of Micro- and Nanostructures. Due to the self-sensing piezoresistive cantilever technology used for the AFM scanner the cantilever deflection signal can be measured completely electrical and allows for simultaneous acquisition of SEM and AFM data directly at the region of interest. We will present a variety of novel case studies to highlight the advantages this new tool for interactive correlative in-situ nanoscale characterization for different materials and nanostructures.<br/><br/>First results will focus on semiconducting BaTiO₃-based ceramics with positive temperature coefficient of resistivity (PTCR) that currently gain increased attention due to their application as cabin heater in electrical vehicles. We use electrostatic force microscopy (EFM) in combination with the SEM in order to precisely analyze the grain boundary potential barriers of different BaTiO₃-based samples. [3] The grain boundaries were located by backscatter electron detection (BSE) and afterwards measured with in-situ EFM. The barriers were shown to be significantly thinner and more pronounced as the amount of SiO₂ was increased from 0 to 5 mol%. These results can be directly correlated with electron backscatter diffraction (EBSD) measurements to link the AFM and SEM data to the crystallographic microstructure of the different samples.<br/><br/>In addition, we will present first results for the in-situ characterization of nanowires that will be used for energy harvesting applications. The SEM enables the easy location of individual or multiple nanaowires, whereas the in-situ AFM allows the characterization of topography, surface roughness, mechanical, and electrical properties of the nanowires.<br/><br/>Based on the broad variety of applications regarding the inspection and process control of different materials and devices, we anticipate that this new inspection tool to be one of the driving characterization tools for correlative SEM and AFM analysis in the future.<br/><br/>[1] D. Yablon, et al., Microscopy and Analysis,<b> 31 </b>(2), 14-18 (2017)<br/>[2] S.H. Andany, et al., Beilstein J. Nanotechnol., <b>11</b>, 1272-1279 (2020)<br/>[3] J.M. Prohinig, J. Hütner, K. Reichmann, S. Bigl, Scripta Materialia, <b>214</b>, 114646 (2022)