Abstract
The surface of samples in atomic force microscopy is studied using cantilevers, which are an elastic console with a sharp needle at the free end. The quality of images obtained with an atomic force microscope (AFM) depends to a large extent on the degree of sharpness of the needle. Single-crystal silicon cantilevers made based on wet anisotropic etching are widely used. In this paper, the dependence of the shape and size of the formed needle on the KOH concentration in the solution is studied. The influence of pyrogenic oxidation and oxidation in an atmosphere of dry oxygen on the sharpness of the needle during the sharpening process is studied. It is determined that at a 70% KOH concentration, needles are formed that have the highest aspect ratio and maximum height. In this case, the shape of the needle is an octagonal pyramid, the side faces of which are formed by eight crystallographic planes of {311} and {131}. It is shown that a two-stage process of sharpening, consisting of pyrogenic oxidation and oxidation in an atmosphere of dry oxygen, makes it possible to form sufficiently sharp probes with a tip radius of 2–5 nm and an apex angle of 14° to 24°, while a one-stage process of needle sharpening based on pyrogenic oxidation produces probes with a radius of about 14 nm. Comparative tests of the fabricated probes are carried out. Using an AFM, images of a test sample of a polycrystalline silicon film with hemispherical grains (HSG-Si) are obtained. It is determined that a statistical parameter such as the relative increment of the surface area Sdr is the most sensitive to the sharpness of the probe for HSG-Si type film surfaces.
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Novak, A.V., Novak, V.R. & Rumyantsev, A.V. Features of the Manufacturing Process of Silicon Needles for Cantilevers. Russ Microelectron 51, 521–527 (2022). https://doi.org/10.1134/S1063739722070071
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DOI: https://doi.org/10.1134/S1063739722070071