Ferricyanide reduction as a probe for the surface chemistry of silicon in aqueous alkaline solutions

Bressers, P.M.M.C.; Pagano, Sandro; Kelly, John J.

doi:10.1016/0022-0728(95)03908-y

Cited by 45 publications

(59 citation statements)

References 16 publications

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“…The general features of the current-potential curves measured at other temperatures (20-70°C) and KOH concentrations (2-10 M) were similar to those shown in Fig. 1 and to results described in the literature [12,[26][27][28][29]. At potentials positive of the open circuit potential (OCP), a pronounced increase of current is observed that reaches a maximum at E p and finally drops sharply to low values.…”

Section: Voltammetry and Etch Rate Measurementssupporting

confidence: 64%

“…Two hydrogen molecules are released for each silicon atom dissolved [10] and Si(OH) 4 is regarded as the primary reaction product [11,12]. The overall reaction is [13,14] Si þ 2H 2 Etching defects and surface roughness can result if the hydrogen bubbles produced remain long enough on the surface to mask it from the etching solution [15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

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Surface termination and hydrogen bubble adhesion on Si(100) surfaces during anisotropic dissolution in aqueous KOH

Haiss

Raisch

Bitsch

et al. 2006

Journal of Electroanalytical Chemistry

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The formation and growth of hydrogen bubbles on a Si(1 0 0) surface during its anisotropic etching in aqueous KOH has been investigated. Quantitative data on bubble size, lifetime and density on the etching surface was obtained and their dependence on KOH concentration, applied potential and temperature were measured. In situ FTIR measurements demonstrated a strong dependence of bubble attachment on surface termination and hence on the hydrophilicity of the Si(1 0 0) surface during etching. The formation of surface defects and the geometry of bubble imprints have been directly characterised with scanning probe microscopy. The analysis of hillock formation and statistical considerations show that the adhesion of hydrogen bubbles during anisotropic etching of silicon is a source of surface roughness and pyramid formation.

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Section: Voltammetry and Etch Rate Measurementssupporting

confidence: 64%

Section: Introductionmentioning

confidence: 99%

Surface termination and hydrogen bubble adhesion on Si(100) surfaces during anisotropic dissolution in aqueous KOH

Haiss

Raisch

Bitsch

et al. 2006

Journal of Electroanalytical Chemistry

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“…Fig. 5B shows three successive CV cycles on bare Si (ultrasonically cleaned) and PT films on silicon, respectively, from 0 V to À1.3 V. The CV for bare silicon shows a large diffusion-limited reduction peak with a maximum of À0.9 V. Diffusion-limited electrochemistry at such large over-potentials is a typical feature on semi-conducting electrodes because the reduction of the solution species takes place via the hole injection into the silicon valence band [37]. The current dramatically decreases over three successive potential cycles, presumably because of the formation of an oxide layer on the silicon surface.…”

Section: Electrochemical Stability and Passivating Properties Of Pt Fmentioning

confidence: 98%

“…Anodisation of silicon in aqueous medium will unavoidably result in the formation of a layer of silicon dioxide or, in the presence of certain electrolytes (fluorides for example), lead to the dissolution of silicon and the formation of pores [4,37]. To investigate the electrochemical reactivity of highly doped silicon electrodes under our electropolymerisation conditions, the CVs in supporting electrolyte solution omitting tyramine were recorded.…”

Section: Electrochemical Polymerisation Of Tyramine On P ++ -Siliconmentioning

confidence: 99%

Ultrathin polytyramine films by electropolymerisation on highly doped p-type silicon electrodes

et al. 2005

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“…‡ Care must be taken since it is the chemical potential of the chemical species that leaves the surface, and this is not necessarily Si(OH) 4 . The last equality applies for a small misalignment.…”

mentioning

confidence: 99%

The form of etch rate minima in wet chemical anisotropic etching of silicon

Elwenspoek¹

1996

J. Micromech. Microeng.

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Abstract. Etching of monocrystalline silicon in alkaline based solutions leads to a deep minimum in the etch rate crystallographically oriented along 111 . The details of the form of the minimum (angular dependence of the etch rate) are investigated and discussed in a framework of steps originating from spontaneous nucleation and from misorientation of the crystal face exposed to the etchant. As a result, the etch rate minimum is characterized by a narrow flat portion that reflects the density of nuclei, and the temperature dependence of the width has an activation energy equal to 1/3 of the nucleation barrier.This article deals with the dependence of the silicon etch rate close to the 111 orientation when etching in anisotropic etching solutions such as aqueous KOH and EDP ‡. In these solutions the etch rate is strongly dependent on the crystallographic orientation of the silicon single crystal, with absolute minima in 111 , and relative minima in 001 (aqueous KOH) and 110 (aqueous KOH saturated with isopropyl alcohol, IPA and EDP). An extensive discussion on experimental results can be found e.g. in [1]. The origin of the anisotropy is being debated in the literature. While many authors try to find explanations based on (electro-) chemical reactions of water or hydroxyl ions with the silicon surface for orientation dependent contributions [1][2][3][4], this author proposed to use models developed for the rate of crystal growth to find the origin of the anisotropy [5][6][7]. This view has consequences on some details of the etch rate diagram (i.e. the variation of the etch rate with the crystallographic orientation) that will be explored here and compared to experimental data taken from the literature. In our view, understanding the anisotropy of the etch rate of silicon (and other singlecrystalline materials, such as quartz and GaAs) is not only interesting from a scientific point of view, but also for the development of micromachining. Wet chemical etching is a key technology for micromachining because it allows fast, precise and reproducible shaping of mechanical microcomponents such as numerous sensors for pressure, force, acceleration, flow, temperature and concentration of chemicals, actuators like pumps, valves, switches and microstructures such as microsieves, canals and nozzles. The major volume is currently being fabricated in research † email: m.elwenspoek@eltn.utwente.nl ‡ Ethylenediamine, pyrocathecol and water mixtures, occasionally with traces of pyridine.laboratories, but scaling up to mass production makes perfect control of the technology necessary, which is very difficult to achieve if the origin of a prominent and important property of the etching-the anisotropy-is not understood. This is a quite formidable task, and this paper will contribute a step towards executing to it.Starting with a short outline of the crystal growth view on wet chemical anisotropic etching, we focus on the kinetics of steps on misoriented flat crystal faces. We have found that there are two competing mechanisms for ...

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Ferricyanide reduction as a probe for the surface chemistry of silicon in aqueous alkaline solutions

Cited by 45 publications

References 16 publications

Surface termination and hydrogen bubble adhesion on Si(100) surfaces during anisotropic dissolution in aqueous KOH

Surface termination and hydrogen bubble adhesion on Si(100) surfaces during anisotropic dissolution in aqueous KOH

Ultrathin polytyramine films by electropolymerisation on highly doped p-type silicon electrodes

The form of etch rate minima in wet chemical anisotropic etching of silicon

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