Platinum Silicide probes: A novel approach to manufacture highly conductive AFM probes with small radii and high wear resistance

O. Krause, A. Sebastian, M. Despont
Nanoworld Services, DE

Keywords: AFM, c-AFM, conductive, tip, probe

Summary:

Conventionally, conductive Atomic Force Microscopy (c-AFM) probes are either made by depositing a metal, an alloy or a doped diamond layer onto a ready-made AFM probe or, alternatively, by depositing one of those materials into an inverted pyramid anisotropically etched into silicon followed by a subsequent tip and cantilever release process (similar to the fabrication of molded SiN probes). Disadvantages of those technologies are the increase of the tip radius due to the additional layers and a fast wear-out behavior of metal coatings. The abrasive resistant diamond needs a certain thickness to form a closed layer (100 nm and more) whereupon the conductivity is a decade worse than that for metal coated probes (e.g. 30 nm PtIr). Moreover conductive tips manufactured by molding, has proven to be rather unreliable in producing sharp tips. In this work we present c-AFM results using a newly developed cantilever with platinum silicide (PtSi) tip, approach which was first reported in. The developed PtSi tips have radii close to that of silicon tips, conductivity similar to commercial PtIr coated probes however, they have an outstanding mechanical wear-out behavior and sustained electrical contact quality.