E J Luber et al 2009 Nanotechnology 20 345703 doi:10.1088/0957-4484/20/34/345703
E J Luber1, B C Olsen1, C Ophus1, V Radmilovic2 and D Mitlin1
Show affiliationsA growing number of atomic force microscope (AFM) applications make use of metal-coated probes. Probe metallization can cause adverse side-effects and disadvantages such as stress-induced cantilever bending, thermal expansion mismatch, increased tip radius and limited device lifetime due to coating wear. In this study we demonstrate how to overcome these limitations using microstructural design to create a metallic glass thin film alloy, from which monostructural all-metal AFM cantilevers are fabricated. A detailed compositional study of co-sputtered Cu–Hf films is performed using x-ray diffraction (XRD), nanoindentation, four-point probe and in situ multi-beam optical stress sensing (MOSS). Metallic glass Cu90Hf10 films are found to possess an optimal combination of electrical resistivity (96 µΩ cm), nanoindentation hardness (5.2 GPa), ductility and incremental stress. A continuum model is developed which uses measured MOSS data to predict cantilever warping caused by stress gradients generated during film growth. Subsequently, a microfabrication process is developed to create Cu90Hf10 AFM probes. Uncurled, 1 µm thick cantilevers having lengths of 100–400 µm are fabricated, with tip radii ranging from 10 to 40 nm. As a proof of principle, these all-metal Cu–Hf AFM probes are mounted in a commercial AFM and used to successfully image a known test structure.
68.55.-a Thin film structure and morphology
62.20.Qp Friction, tribology, and hardness
68.60.Bs Mechanical and acoustical properties
68.37.Ps Atomic force microscopy (AFM)
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
Issue 34 (26 August 2009)
Received 25 April 2009, in final form 26 June 2009
Published 4 August 2009
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