Tip wear and tip breakage in high-speed atomic force microscopes

Tip abrasion is a critical issue particularly for high-speed atomic force microscopy (AFM). In this paper, a quantitative investigation on the tip abrasion of diamond-like-carbon (DLC) coated tips in a high-speed metrological large range AFM device has been detailed. Wear tests are conducted on four different surfaces made of silicon, niobium, aluminum and steel. During the tests, different scanning speeds up to 1 mm/s and different vertical load forces up to approximately 33.2 nN are applied. Various tip characterization techniques such as scanning electron microscopy (SEM) and AFM tip characterizers have been jointly applied to measure the tip form change precisely. The experimental results show that tip form changes abruptly rather than progressively, particularly when structures with steep sidewalls were measured. This result indicates the increased tip breakage risk in high-speed AFM measurements. To understand the mechanism of tip breakage, tip-sample interaction is modelled, simulated and experimentally verified. The results indicate that the tip-sample interaction force increases dramatically in measurement scenarios of steep surfaces.