Assessment of the mechanical integrity of silicon and diamond-like-carbon coated silicon atomic force microscope probes

The wear of atomic force microscope (AFM) tips is a critical issue in the performance of probe-based metrology and nanomanufacturing processes. In this work, diamond-like carbon (DLC) was coated on Si AFM tips using a plasma ion implantation and deposition process. The mechanical integrity of these DLC-coated tips was compared to that of uncoated silicon tips through systematic nanoscale wear testing over scan distances up to 0.5 meters. The wear tests consisted of a combination of contact-mode AFM scanning, transmission electron microscopy, and pull-off force measurements. Power spectral density analysis of AFM measurements acquired on structured samples was used to evaluate the imaging performance of the tips. The results show that Si tips are prone to catastrophic failure in self-mated contacts under typical scanning conditions. In contrast, DLC-coated tips demonstrate little to no measurable wear under adhesive forces alone, and exhibit stress-dependent gradual wear under external loads of ~22 and 43 nN.