1. Institute of Electron Devices and Circuits Ulm University Albert‐Einstein‐Allee 45 89081 Ulm Germany
2. Central facility of Electron Microscopy Ulm University Albert‐Einstein‐Allee 11 89081 Ulm Germany
3. Institute of Micro‐ and Nanotechnologies Microsystems Technology Group Technische Universität Ilmenau Max‐Planck‐Ring 12 98693 Ilmenau Germany