Anisotropic Etching of Crystalline Silicon in Alkaline Solutions: II . Influence of Dopants

Seidel, H.; Csepregi, L.; Heuberger, A.; Baumgärtel, H.

doi:10.1149/1.2086278

Cited by 455 publications

(425 citation statements)

References 13 publications

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“…16 In the case of B-dopant, the etch rate reduction up to three orders of magnitude could be obtained for Si electrodes with increasing the boron concentration from 10 19 /cm 3 to 10 20 /cm 3 . 16,23 Although the etch rate reduction for highly doped Si electrodes in strongly acidic solutions was not observed, 16,24 we assume that EMIm(HF) 2.3 F ionic liquid shows similar behavior to alkaline media. Moreover, the chemical and electrochemical behavior of heavily-doped Si electrodes in EMIm(HF) 2.3 F ionic liquid are still unknown and more investigations are needed to understand the influence of dopant concentrations and crystal orientations of Si electrodes.…”

Section: Discussionmentioning

confidence: 98%

Influence of Dopant Type and Orientation of Silicon Anodes on Performance, Efficiency and Corrosion of Silicon–Air Cells with EMIm(HF)_2.3F Electrolyte

Durmus

Jakobi

Beuse

et al. 2017

J. Electrochem. Soc.

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Intermediate term discharge experiments were performed for Si-air full cells using As-, Sb-and B-doped Si-wafer anodes, with 100 and 111 orientations for each type. Discharge characteristics were analyzed in the range of 0.05 to 0.5 mA/cm 2 during 20 h runs, corrosion rates were determined via the mass-change method and surface morphologies after discharge were observed by laser scanning microscopy and atomic force microscopy. Corresponding to these experiments, potentiodynamic polarization curves were recorded and analyzed with respect to current-potential characteristics and corrosion rates. Both, discharge and potentiodynamic experiments, confirmed that the most pronounced influence of potentials -and thus on performance -results from the dopant type. Most important, the corrosion rates calculated from the potentiodynamic experiments severely underestimate the fraction of anode material consumed in reactions that do not contribute to the conversion of anode mass to electrical energy. With respect to materials selection, the estimates of performance from intermediate term discharge and polarization experiments lead to the same conclusions, favoring 100 and 111 As-doped Si-wafer anodes. However, the losses in the 111 As-doped Si-anodes are by 20% lower, so considering the mass conversion efficiency this type of anode is most suitable for application in non-aqueous Si-air batteries. One line of development in technologies for electrical energy storage is metal-air batteries, which provide high specific energies and -when referring to Zn, Al, Fe, or Si -are at the same time resource effective with respect to the availability and price of the anode materials. The theoretical specific energy of a Si-air cell, related to the anode mass only, is 8470 Wh/kg. Using Si material in aqueous alkaline solutions, however, results in a severe corrosion reaction which is accompanied by intense hydrogen evolution.1-3 Despite the corrosion reaction, it is still feasible to build an alkaline Si-air cell at a discharge potential around 1.1 V, however, with sacrifice of huge amount of Si anode to corrosion. [4][5][6] Therefore, new approaches to establish batteries on silicon materials have been put forward using ionic liquid electrolytes. One of the possible approaches is the usage of EMIm(HF) 2.3 F electrolyte which possesses high conductivity, low viscosity and chemical stability in air.7-10 The proof of concept, that substantial discharge was possible when using EMIm(HF) 2.3 F electrolyte, was proposed in 2010 according to the following reactions: Additionally, a screening of several anode materials -As-, Sband B-doped Si wafers -was performed, in which the cell potential at intermediate current densities as determined from potentiodynamic polarization measurements, was set as major criterion. The corrosion current densities as obtained by the Tafel fits from the polarization experiments for the different wafer types were also considered for the material selection. However, owing to the low corrosion rates, it played a minor ro...

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Section: Discussionmentioning

confidence: 98%

Influence of Dopant Type and Orientation of Silicon Anodes on Performance, Efficiency and Corrosion of Silicon–Air Cells with EMIm(HF)_2.3F Electrolyte

Durmus

Jakobi

Beuse

et al. 2017

J. Electrochem. Soc.

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“…Therefore, our morphological design strategy can be applied to improve the fracture behavior not only of nanopillars or nanoparticles but also of c-Si structures of larger dimensions as long as bulk diffusion process is much faster than the interface reaction kinetics. Whereas synthesis of anisometric Si nanostructures may be accomplished through anisotropic crystal growth 41 or etching [42][43][44] , anisometric micron-sized Si structures such as micropillars can be more easily and precisely fabricated by conventional photolithography techniques. We recently prepared both p-type and n-type silicon micropillar arrays (diameter = 2 µm) with different cross section shapes on (100) Si wafers using plasma etching, and electrochemically lithiated them in lithium half cells 45 (details of the fabrication and electrochemical test methods can be found in the Supporting Information).…”

Section: Morphological Design Of C-si Anodementioning

confidence: 99%

Mitigating mechanical failure of crystalline silicon electrodes for lithium batteries by morphological design

Wood

et al. 2015

Phys. Chem. Chem. Phys.

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Although crystalline silicon (c-Si) anodes promise very high energy densities in Li-ion batteries, their practical use is complicated by amorphization, large volume expansion and severe plastic deformation upon lithium insertion. Recent experiments have revealed the existence of a sharp interface between crystalline Si (c-Si) and the amorphous Li x Si alloy during lithiation, which propagates with a velocity that is orientation dependent; the resulting anisotropic swelling generates substantial strain concentrations that initiate cracks even in nanostructured Si. Here we describe a novel strategy to mitigate lithiation-induced fracture by using pristine c-Si structures with engineered anisometric morphologies that are deliberately designed to counteract the anisotropy in the crystalline/amorphous interface velocity. This produces a much more uniform

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“…The following discussion concerning the difference in the Cu collection efficiency on the p + -type silicon surface is based on the band model reported by Seidel et al 15 According to their band model, the width of the space-charge layer on the silicon surface is shrunk sharply because of a high concentration of boron. This leads to an equivalent narrowing of the potential well, which cannot confine the electrons injected into the conduction band by the oxidation step (Eq.…”

Section: Resultsmentioning

confidence: 99%

Collection Efficiency of Metallic Contaminants on Si Wafer by Vapor-Phase Decomposition-Droplet Collection

Chung¹,

Kim²,

Cho³

et al. 2001

ANAL. SCI.

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Metallic contaminants on a wafer surface have been known to be a major source of performance failure in IC devices by increasing the p-n junction leakage, degradation of the oxide breakdown voltage and deteriorating the carrier lifetime. 1 With shrinking device geometries, the tolerance level of metallic contaminants is becoming more stringent. It has been reported that metallic contamination on a silicon surface needs to be suppressed to less than 1 × 10 10 atoms/cm 2 to manufacture a 64-Mbit DRAM in order to prevent the above-mentioned failures. 2 According to device development and an estimation of the research organization, this level should be down to 1 × 10 9 atoms/cm 2 in the future. With this tendency, analytical techniques used to measure ultratrace metallic contaminants on a silicon surface have also been developed.One of the most prevalent techniques used for measuring metallic contaminants is VPD-DC (vapor phase decompositiondroplet collection). During the VPD procedure, the wafer is exposed to hydrogen fluoride vapor in a closed container to decompose the surface oxide layer. The decomposition reaction of silicon oxide by hydrogen fluoride vapor is expressed by SiO2 + 6HF ⇔ H2SiF6 + 2H2O.(1)Metallic contaminants remain on the wafer surface after the decomposition of silicon oxide. In the DC procedure, these metallic contaminants are collected into a small amount of ultrahigh-purity liquid droplets by scanning the wafer surface. A liquid droplet prepared by VPD-DC is analyzed by different trace-element analysis techniques, such as atomic absorption spectrometry (VPD-AAS), 3-7 inductively coupled plasma-mass spectrometry (VPD-ICP-MS) 5,8-10 and total reflection X-ray fluorescence (VPD-TXRF). 4,[11][12][13] DC is a procedure used to collect and preconcentrate all impurities into liquid droplets. The composition of the collecting solution as well as the chemistry of the collected contaminants determine the collection efficiency. Morinaga et al. have reported that metallic contaminants deposit on a silicon wafer surface in a wet process depending on the type of metal element, the type of solution and the type of substrate. 14 Therefore, a chemical reaction of metal at the silicon surface during VPD-DC can influence the collection efficiency of a metallic contaminant. However, there have been few reports concerning the collection efficiency of the VPD-DC procedure. In this experiment, the collection efficiency of VPD-DC sample preparation was investigated for 14 elements (Na, Mg, Al, K, Ca, Cr, Fe, Mn, Co, Ni, Cu, Zn, Mo and Ti) on four types of silicon wafers. Standard solutions containing 7 elements in each solution were intentionally contaminated on a silicon wafer surface. The contaminated area was scanned with various collecting solutions in the VPD-DC procedure and a droplet containing metallic contaminants, collected from the silicon wafer surface, was measured by ICP-MS. The collection efficiency was determined as the ratio of the collected metallic concentration to the initial contamination conce...

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Anisotropic Etching of Crystalline Silicon in Alkaline Solutions: II . Influence of Dopants

Cited by 455 publications

References 13 publications

Influence of Dopant Type and Orientation of Silicon Anodes on Performance, Efficiency and Corrosion of Silicon–Air Cells with EMIm(HF)_2.3F Electrolyte

Influence of Dopant Type and Orientation of Silicon Anodes on Performance, Efficiency and Corrosion of Silicon–Air Cells with EMIm(HF)_2.3F Electrolyte

Mitigating mechanical failure of crystalline silicon electrodes for lithium batteries by morphological design

Collection Efficiency of Metallic Contaminants on Si Wafer by Vapor-Phase Decomposition-Droplet Collection

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Anisotropic Etching of Crystalline Silicon in Alkaline Solutions: II . Influence of Dopants

Cited by 455 publications

References 13 publications

Influence of Dopant Type and Orientation of Silicon Anodes on Performance, Efficiency and Corrosion of Silicon–Air Cells with EMIm(HF)2.3F Electrolyte

Influence of Dopant Type and Orientation of Silicon Anodes on Performance, Efficiency and Corrosion of Silicon–Air Cells with EMIm(HF)2.3F Electrolyte

Mitigating mechanical failure of crystalline silicon electrodes for lithium batteries by morphological design

Collection Efficiency of Metallic Contaminants on Si Wafer by Vapor-Phase Decomposition-Droplet Collection

Contact Info

Product

Resources

About

Influence of Dopant Type and Orientation of Silicon Anodes on Performance, Efficiency and Corrosion of Silicon–Air Cells with EMIm(HF)_2.3F Electrolyte

Influence of Dopant Type and Orientation of Silicon Anodes on Performance, Efficiency and Corrosion of Silicon–Air Cells with EMIm(HF)_2.3F Electrolyte