Silicon nitride cantilevers with oxidation-sharpened silicon tips for atomic force microscopy

Grow, Randal J.; Minne, S. C.; Manalis, Scott R.; Quate, C. F.

doi:10.1109/jmems.2002.800924

Cited by 53 publications

(24 citation statements)

References 11 publications

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“…The analysis of this figure shows that when low-stress viscosity is increased, the stress effects are more pronounced, leading to a sharper tip. Above a value of 5 10 P for , mechanical stresses and the induced nonlinearity are so high, and the algorithm cannot converge, with the relaxation factor value, which has been fixed . Inversely, as soon as the low-stress viscosity decreases and falls below the value of 10 P, the oxidation rate increases considerably and the profile curves assume the same shape as when mechanical stresses are not taken into account (the geometrical effect is no longer counterbalanced by the mechanical stresses).…”

Section: ) Plasticity Threshold Coefficient Influence: the Curves Inmentioning

confidence: 99%

“…They are integrated as emitter sources in field emitter devices for flat-panel display applications [1]- [4] as probes in atomic force microscopes [5] and scanning tunneling microscopes [6], as write/read/erase heads in nanomechanical storage devices [7], as microneedles for the mechanical insertion of genes in cells [8], and can be integrated as potential vibrating elements [9] in microelectromechanical systems (MEMS) devices [10], [11]. One main challenge of all the aforementioned applications is fabricating sharp tips such that the radius of curvature at their apex is less than 10 nm.…”

Section: Introductionmentioning

confidence: 99%

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Modeling and Experimental Validation of Sharpening Mechanism Based on Thermal Oxidation for Fabrication of Ultra-Sharp Silicon Nanotips

Agache¹,

Ringot²,

Bigotte³

et al. 2005

IEEE Trans. Nanotechnology

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This paper aims at modeling the thermal oxidation of silicon pillars leading to the formation of very sharp silicon tips. The model is used to determine optimum process parameters with respect to the initial shape of the silicon pillars and the geometry of the desired tip. The modeling concept is to extend a previous approach, which predicts the oxidation mechanism of silicon cylinders versus their initial radius. The silicon pillar geometry is approximated by a superposition of silicon cylindrical structures featuring a local curvature radius. Experimental validation has been performed for several initial silicon pillar shapes, at 1000 C and 1100 C under dry oxidation conditions, leading to formation of very sharp silicon tips. The numerical predictions are shown to agree well with these experimental data. The motivation of this study aims at designing and fabricating a nanoelectromechanical filter device. Its vibrating part consists of a silicon nanotip, covered with a thin gold layer, the geometrical features of which affect the center frequency of the nanofilter device.

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Section: ) Plasticity Threshold Coefficient Influence: the Curves Inmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modeling and Experimental Validation of Sharpening Mechanism Based on Thermal Oxidation for Fabrication of Ultra-Sharp Silicon Nanotips

Agache¹,

Ringot²,

Bigotte³

et al. 2005

IEEE Trans. Nanotechnology

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“…Sharp silicon tips have extensive applications in nanoelectromechanical system and biomedical field, such as AFM probe, field emission tip, and microneedle array (Folch et al 1997;Grow et al 2002;Yang et al 2005;Sun et al 2012;Kim et al 2012). Small tip apex and high aspect ratio are normally desired for good performance.…”

Section: Introductionmentioning

confidence: 99%

Silicon tip sharpening based on thermal oxidation technology

Zhang

Yang

et al. 2016

Microsyst Technol

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Silicon tips are conventionally fabricated by isotropic etching followed by oxidation sharpening at temperatures below 1050 °C, based on the reduced oxidation rate at the step edge due to high compressive stress around the edge (Marcus and Sheng 1982). However, the effects of the oxidation temperature on the tip profile have been far from studied yet. This work investigated in detail the optimized oxidation temperature to fabricate sharp tips with high aspect ratio. The results indicated that a trade-off between aspect ratio and the tip diameter should be taken into account when choosing the oxidation temperature. Sharp silicon tip with a diameter of 6.3 nm was fabricated. Figure 1 described the fabrication process of the silicon tips. First, A 300 nm thick oxide was thermally grown on 4-inch (100) silicon wafer substrate as the mask. The lithography was performed to define the tip apex, and the pattern was transferred to the thermal oxide by reactive ion etching (RIE). Then silicon etching was followed by isotropic dry etching using RIE to get the silicon posts. After isotropically etching Si to a depth of 6 um, a neck was formed about 1 micron below the mask, located at the thinnest part of the silicon post, as illustrated in Fig. 1d. Silicon necks with widths between 97 and 330 nm were produced by changing the mask sizes. The oxide mask was removed by buffered hydrofluoric (BHF) acid solution and the silicon posts or "pre-tips" were formed. Figure 3a-c shows the SEM photographs of the fabricated silicon posts. Experimental arrangementsFour groups of silicon post samples were prepared and thermal oxidation were performed at temperatures of 900, 950, 1000, and 1050 °C, respectively. Low temperature oxidation has been studied to sharpen silicon tips (Umimoto Abstract Thermal oxidation at low temperatures (below 1050 °C) is widely used in the microfabrication of sharp silicon tips. However, the influences of the oxidation temperature on morphology of the tips have not been investigated in detail. This work systematically studied the dependence of tip profile on the oxidation temperature. Thermal oxidation were performed in four groups at 900, 950, 1000 and 1050 °C. The results show that a trade-off between the tip aspect ratio and diameter should be taken into account when choosing the oxidation temperature. The optimized oxidation temperature to make tips with small apex, high aspect ratio, and smooth surface is around 1000 °C. The tip with a diameter of 6.3 nm was realized through oxidation at 1000 °C.

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“…Work in the area of sensor and actuator development for atomic force microscopy [Manalis et al, 1996;Grow et al, 2002] has provided additional reasons to pursue physical modeling using microfabrication methods. Utilizing atomic force microscopy techniques, a model with active mechanisms could be developed.…”

Section: Introductionmentioning

confidence: 99%

Developing a Physical Model of the Human Cochlea Using Microfabrication Methods

Steele

Puria

2006

Audiol Neurotol

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Advances in micromachining technology have provided the opportunity to explore possibilities of creating life-sized physical models of the cochlea. The physical model of the cochlea consists of two fluid-filled channels separated by an elastic partition. The partition is micromachined from silicon and uses a 36-mm linearly tapered polyimide plate with a width of 100 µm at the basal end and 500 µm at the apex to represent the basilar membrane. Thicknesses from 1 to 5 µm have been fabricated. Discrete aluminum fibers (1.5 µm in width) are machined to create direction-dependent properties. A 0.5 × 0.5 mm opening represents the helicotrema. The fluid channels are machined from plexiglas using conventional machining methods. A magnet-coil system excites the fluid channel. Measurements on a model with thickness 4.75 µm show a velocity gain of 4 and phase of 3.5 π radians at a location 23 mm from the base. Mathematical modeling using a 3-D formulation confirm the general characteristics of the measured response.

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Silicon nitride cantilevers with oxidation-sharpened silicon tips for atomic force microscopy

Cited by 53 publications

References 11 publications

Modeling and Experimental Validation of Sharpening Mechanism Based on Thermal Oxidation for Fabrication of Ultra-Sharp Silicon Nanotips

Modeling and Experimental Validation of Sharpening Mechanism Based on Thermal Oxidation for Fabrication of Ultra-Sharp Silicon Nanotips

Silicon tip sharpening based on thermal oxidation technology

Developing a Physical Model of the Human Cochlea Using Microfabrication Methods

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