Combined magnetic and conductive AFM probe via FEBID based 3D nanoprinting

Atomic Force Microscopy (AFM) has evolved to be an essential imaging tool in many fields of
research and industry. Rastering a sharp probe across the sample surface allows to avoid
Abbe’s limit enabling sub-nm resolution, while a wide range of atmospheres including liquid
conditions or vacuum are applicable. In addition to the sample surface topography, further
information can simultaneously be accessed using functionalized AFM probes. Common
modifications allow imaging of magnetic, electrical, optical or thermal surface properties and
are usually based on standard probes with functional coatings. An alternative approach are
dedicated functional probes via Focused Electron Beam Induced Deposition (FEBID). In this
contribution, we introduce a yet unexplored probe concept, which enables conductive AFM
(CAFM) and Magnetic Force Microscopy (MFM) in a single experiment. Whilst the former is
typically performed in contact mode with a soft cantilever, the latter requires an oscillating
cantilever of higher stiffness, which would in turn increase contact forces in contact mode
AFM. Here, we demonstrate an ideal compromise between both worlds. Our probe tip is
printed via FEBID from a Co3Fe precursor, yielding a highly crystalline probe with minor
carbon and oxygen remains. Such tips have recently demonstrated superior MFM
performance and, in principle, should be electrically conductive as well. In the first step, such
probes were subjected to wear tests revealing sufficient wear resistance even for harder
cantilever. In the next step, the probe concept was adopted to self-sensing cantilever
systems, enabling the application in a deeply integrated SEM-AFM system, FUSIONScope™
(Quantum Design Microscopy). Here the combined AFM probe can be used to its full
potential by seamless addition of measurement capabilities without switching between
probes, illustrated on different samples. By that, we can report another AFM probe concept
via FEBID based 3D nanoprinting.