Design and fabrication of in-plane AFM probes with sharp silicon nitride tips based on refilling of anisotropically etched silicon moulds

Abstract

In this paper a micromachining method for batch fabrication of in-plane atomic force microscope (AFM) probes that consist of a sharp silicon nitride tip on a monocrystalline silicon cantilever is presented. The tips are realized by conformal deposition of silicon nitride inside an anisotropically etched cavity inside a silicon wafer. The best measured radius of the sharp tips was 8 nm. Our fabrication method is fully compatible with silicon-on-insulator (SOI) micromachining, allowing a straightforward monolithic integration of the AFM probes with high-aspect-ratio monocrystalline silicon MEMS. The fabrication method allows for lateral cantilevers, which oscillate in the plane of the fabrication wafer. This allows for simple integration of micromechanical transducers, opening the way towards dedicated probes for high speed AFMs. To demonstrate the innovation potential of this method, three different probe designs were fabricated: a plane passive AFM probe, a probe with integrated electrostatic actuator, and a probe which allows scanning on vertical sidewalls. The passive probes were successfully tested in a commercial AFM set-up. Correct operation of the probes with integrated actuator was demonstrated by actuation under a laser vibrometer.

Highly uniform sieving structure by corner lithography and silicon wet etching

“…8a-c). This deviation primarily results from limitations in mask resolution and variations in the mask transfer by UVlithography, rather than due to wet etching as these processes are based on self-alignment [16].…”

Numerical modeling of capillary electrophoresis - electrospray mass spectrometry interface design

“…The very good overall agreement between the experimental and numerical results reliably validated their model, even in complex cases. Others (Geerlings et al, ) published a simplified mode to represent the interaction between the applied electric forces and mechanical momentum in the electrospray process. Unfortunately, their model was limited just for a given range, restricting the usefulness of their efforts.…”

Lateral Fractal Formation by Crystallographic Silicon Micromachining

“…Corner lithography is used to fabricate octahedral features and fractals [4], 3D nanowires [5,6], 3D nanoapertures at the apex of pyramids [4,5,7], nanoring particles and photonic crystals [8], fluidic components [6], and high-aspect-ratio octahedra and donut-like structures [9]. These structures have been applied in AFM probes [4,6,10], gas permeation [11], and cell trapping devices [6].…”