For the navigation of four independent STM probe tips, simultaneous scanning electron microscopy (SEM) s indispensable. This enables a large field of view for probe coarse positioning as well as fine positioning and rapid localisation of nanometer-sized structures with the SEM's high resolution capabilities.
As the ultimate tool for rapid localization, the UHV Gemini column also gives access to chemical mapping by Scanning Auger Microscopy, magnetic imaging by SEM with polarisation analysis (SEMPA), and other electron spectroscopy methods. This unique combination of different techniques at the same position on the sample yields complementary information on sample conductance, topography, chemistry or magnetism.
Advancing the UHV Gemini column SEM resolution to below 4 nm in the UHV NANOPROBE has great impact on the capabilities of a nanoprobing system. It allows for the localisation of extremely small structures as well as rapid and precise positioning of probes by truly simultaneous SEM and STM operation. Even if the SEM beam current is in the range of the tunnelling current, the STM performance remains virtually unaffected.
The low beam energy performance of the UHV Gemini column minimises damage of sensitive samples and enables imaging of nearly insulating samples by minimising charging effects at energies in the 1 keV range. The hydrocarbon-free UHV environment avoids electron-beam-induced graphite formation and ensures stable imaging and ultra-clean conditions. Alternatively, various other UHV SEM columns or optical microscopes can cover the resolution range from the µm scale down to 20 nm if sample structures do not require the ultimate resolution provided by the UHV Gemini column.