Electrochemical characterization of Si in tetra-methyl ammonium hydroxide (TMAH) and TMAH:Triton-X-100 solutions under white light effects

Conway, Elizabeth M; Cunnane, Vincent J.

doi:10.1088/0960-1317/12/2/307

Cited by 18 publications

(16 citation statements)

References 38 publications

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“…An anodic shift of the OCP with increased etching time was observed. This anodic shift was due to the exposure of the slow etching (111) planes as formation of the 'V' grooves occurs, as shown in figure 2(c) (since the OCP of p(111) Si is more anodic than the OCP for p(100) [26,27]). This anodic shifting started earlier during etching for the higher temperature, as was observed from the significantly sharper slope at 82 • C, compared to etching at 52 • C (figure 8).…”

Section: Surface Roughness and Etch Rate Measurementsmentioning

confidence: 93%

Effects of chemical pre-treatments on the etching process of p(100) Si in tetra-methyl ammonium hydroxide solution

Conway

Cunnane²

2001

J. Micromech. Microeng.

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An electrochemical approach has been used to study the influence of chemical pre-treatments on the etching characteristics of p-Si(100) in 5.0 wt% tetra-methyl ammonium hydroxide (TMAH) at two distinct temperatures. Linear sweep voltammetry was employed to monitor how various parameters altered with increased etching time. A new type of surface roughness indicator was used to determine the 'surface roughness' as a function of etching time. A similar steady-state 'surface roughness' value was reached for all chemical treatments. Ex situ atomic force microscopy was employed to confirm the differences in surface morphology for the distinct types of chemical pre-treatments. Results showed that both the etching characteristics and final etched structure of p(100) Si in TMAH depended on the initial state of the surface (whether it was hydrophilic or hydrophobic). In particular, increased surface roughening, after short etching times in TMAH, could be related to the increased wetting ability of the initial surface. Also, a rougher surface was produced at a higher temperature. This unexpected result is explained in terms of the non-catalytic role of the tetra-methyl ammonium cation during oxide dissolution.

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Section: Surface Roughness and Etch Rate Measurementsmentioning

confidence: 93%

Effects of chemical pre-treatments on the etching process of p(100) Si in tetra-methyl ammonium hydroxide solution

Conway

Cunnane²

2001

J. Micromech. Microeng.

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“…New techniques should be applied to improve the roundness of the 3D structure and modulate its curvature precisely. Recently, various additives have been studied to improve the etching characteristics of a TMAH solution [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. Among these additives, C 14 H 22 O (C 2 H 4 O) n , n = 9–10 (Triton-X-100) can slow down the etching rate of the affected surface orientation, which is frequently exploited for new 3D microstructures.…”

Section: Introductionmentioning

confidence: 99%

Curvature-Modulated Si Spherical Cap-Like Structure Fabricated by Multistep Ring Edge Etching

Wang

2020

Micromachines

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To create approximately spherical structures with curved sidewalls, this paper presents a method for building a series of decreasing slopes along the sidewall of a circular truncated cone. The multistep ring-edge etching technology of first reducing the concentric mask and then cutting the top off to create a mesa shape can be used to form the slopes. This wet-etching method avoids the constraints of crystallographic properties with surfactant-added Tetramethylammonium hydroxide (TMAH), enabling the manufacture of successive given inclination angles, the precise modulation of the spherical curvature by reduction design of concentric masks, and the setting of etching time. The newly approximated spherical Si microstructure patterns can be used for microlenses, quartz crystal resonators, micropulleys, and other applications. The present research is an approach to fabricate advanced microelectromechanical systems (MEMS) curved-surface structures, extending the range of 3D structures fabricated by silicon wet etching.

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“…5. In general, TMAH is more IC compatible, less toxic, and more stable [14] than other alkaline-based wet etchant, such as potassium hydroxide. SCS micromirrors made by wet etching are stress free and flat due to crystal orientation.…”

Section: Design and Fabricationmentioning

confidence: 99%

Low-Actuation-Voltage MEMS for 2-D Optical Switches

Hsieh

Chiu²,

Tsao³

et al. 2006

J. Lightwave Technol.

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This paper discusses the design, fabrication, and test results of electromagnetically actuated two-dimensional (2-D) microelectromechanical systems (MEMS) optical switches. The switching element consists of a 20 µm × 500 µm × 1200 µm vertical micromirror, which is monolithically integrated with an actuation flap. The micromirror is made by anisotropic tetramethyl-ammonium-hydroxide wet etching with an optical insertion loss of about 0.2 dB. A maximum insertion loss of 2.1 dB has been experimentally demonstrated for a 10 × 10 2-D optical crossconnect switch. The actuation flap has double layers of spiral metal coils to generate a large actuation force with the permanent magnets placed at the bottom of the MEMS chip. The magnetic flux is created on the surface of a pair of opposite polarized magnets to precisely control the moving direction of the vertical mirror. The required voltage is less than 0.5 V, and the power consumption is about 3.5 mW for a switching element. Due to the center symmetric design and the stress-free characteristic of the micromirror, the temperature dependence loss is demonstrated to be as low as 0.05 dB. A switching time of 5 ms is achieved by applying the proper driving waveform.

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Electrochemical characterization of Si in tetra-methyl ammonium hydroxide (TMAH) and TMAH:Triton-X-100 solutions under white light effects

Cited by 18 publications

References 38 publications

Effects of chemical pre-treatments on the etching process of p(100) Si in tetra-methyl ammonium hydroxide solution

Effects of chemical pre-treatments on the etching process of p(100) Si in tetra-methyl ammonium hydroxide solution

Curvature-Modulated Si Spherical Cap-Like Structure Fabricated by Multistep Ring Edge Etching

Low-Actuation-Voltage MEMS for 2-D Optical Switches

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