title: Focused ion beam-assisted fabrication of soft high-aspect ratio silicon nanowire atomic force microscopy probes.
abstract: In this study, high-aspect ratio silicon nanowire (SiNW) - modified atomic force microscopy (AFM) probes are fabricated using focused ion beam (FIB) microfabrication technology and vapor-solid-solid synthesis. Commercially available soft silicon nitride probes are used for localized nanowire growth yielding soft high-aspect ratio AFM probes. The SiNW-modified cantilevers are used here for imaging in PeakForce Tappingۛ (PFT) mode, which offers high force control along with valuable information about tip-sample adhesion. A platinum catalyst, deposited accurately at a truncated AFM tip by ion beam-induced deposition (IBID), was used for localized nanowire synthesis. It could be shown that the deposition of a thin silicon dioxide layer prior to the catalyst deposition resulted in controlled SiNW growth on silicon as well as silicon nitride probes. In addition, a FIB-based method for post-growth alignment of the fabricated SiNW tips is presented, which allows tilt-compensation specifically tailored to the specifications of the used AFM instrumentation. To demonstrate the capability of such soft, high-aspect ratio AFM probes, optical gratings fabricated in GaAs and silver halide fibers were imaged in PFT mode. Additionally, the mechanical stability of these high-aspect AFM probes was evaluated on a sapphire substrate.
authors.affiliation: Institute of Analytical and Bioanalytical Chemistry, Ulm University, 89081, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Knittel
authors.affiliation: Institute of Electron Devices and Circuits, Ulm University, 89081, Germany.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Hibst
authors.affiliation: Institute of Analytical and Bioanalytical Chemistry, Ulm University, 89081, Germany.
authors.forename: Boris
authors.initials: B
authors.lastname: Mizaikoff
authors.affiliation: Institute of Electron Devices and Circuits, Ulm University, 89081, Germany.
authors.forename: Steffen
authors.initials: S
authors.lastname: Strehle
authors.affiliation: Institute of Analytical and Bioanalytical Chemistry, Ulm University, 89081, Germany. Electronic address: christine.kranz@uni-ulm.de.
authors.forename: Christine
authors.initials: C
authors.lastname: Kranz
keywords: Focused ion beam technology; High-aspect ratio AFM probes; Nanowire alignment; Pt catalyst; Silicon nanowires