HF-HNO3-H2SO4/H2O Mixtures for Etching Multicrystalline Silicon Surfaces: Formation of NO2+, Reaction Rates and Surface Morphologies

Lippold, Marcus; Patzig-Klein, S.; Kroke, Edwin

doi:10.5560/znb.2011.66b0155

Cited by 12 publications

(4 citation statements)

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“…This fact, can be explained by the reduction of HF dissociation with increasing H 2 SO 4 concentration and formation of fluorosulfuric acid (Eq. (1)), which leads to a reduction of reactive fluoride ions (F − , HF 2− ) and a consequent decrease of the tantalum oxide dissolution rate [20,21]. Moreover, higher sulfuric acid concentrations also increase the solution viscosity and hinders the diffusion of fluoride-containing species (HF, F − and HF 2− ) to the surface, further limiting the oxide dissolution rate [21].…”

Section: Resultsmentioning

confidence: 99%

Passivation and dissolution mechanisms in ordered anodic tantalum oxide nanostructures

Alves

Ferreira

et al. 2020

Applied Surface Science

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Tantalum oxide (Ta 2 O 5 ) nanostructures exhibit outstanding electrical and optical properties, as well as, high chemical resistance and stability. These materials have great potential for biomedical, catalysis, semiconductors and energy applications due to their large surface area and high specific charge, when arranged in nanoporous or nanotubular morphologies. In order to obtain these structures, an anodization process, which is inexpensive, reproducible and easy to scale up, is used. Yet, depending on the anodization conditions, the formation of a nanoporous or nanotubular layer is difficult to stabilize during the anodization process. In this regard, anodized tantalum oxide nanostructures were produced to understand the effect of the anodization conditions, including electrolyte concentration, potential and time. The nanopores or nanotubes morphologies, their chemical composition and structure were investigated by FIB-SEM, double-corrected TEM-STEM and EDS. We found that it is necessary to have high acid concentrations (mixture of H 2 SO 4 with HF) to be able to form nanoporous or nanotubular structures. Despite the capacity of HF to dissolve and create anodic oxide nanostructures, the amount of H 2 SO 4 concentration in the mixture is very important, leading to a dimple morphology. Furthermore, the increase of the anodization potential/electrical field clearly leads to an increase in the dimples diameter.

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Section: Resultsmentioning

confidence: 99%

Passivation and dissolution mechanisms in ordered anodic tantalum oxide nanostructures

Alves

Ferreira

et al. 2020

Applied Surface Science

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“…In silicon technology, wet silicon etching in chemical solutions based on a blend of hydrofluoric acid (HF), nitric acid (HNO 3 ), and water or other acids is frequently used. Wafer thinning and surface cleaning, [8][9][10] chemical-mechanical polishing (CMP) of the Si surface, [11][12][13][14][15][16][17] and elimination of saw damage [18][19][20] are all obtained by wet-chemical etching processing. The production of water-soluble complexes (SiF 6 , HSiF 6 , and others) and/or fluorosilanes (SiF 4 , HSiF 3 , and others) by hydrofluoric acid are both necessary for the acidic etching of silicon.…”

Section: Introductionmentioning

confidence: 99%

“…Surface texturing can improve internal light absorption over flat‐surfaced cells and substantially minimize reflection on a cell's surface. [ 6,7 ] The Si surface cleaning, [ 8–10 ] chemical–mechanical polishing (CMP) of the Si surface, [ 11–17 ] and elimination of saw damage [ 18–20 ] are all obtained by wet‐chemical etching processing. The production of water‐soluble complexes (SiF 6 , HSiF 6 , and others) and/or fluorosilanes (SiF 4 , HSiF 3 , and others) by hydrofluoric acid are both necessary for the acidic etching of silicon.…”

Section: Introductionmentioning

confidence: 99%

Exploring mc‐Silicon Wafers: Utilizing Machine Learning to Enhance Wafer Quality Through Etching Studies

Raji,

Balakrishnapillai Suseela,

Manikkam

et al. 2024

Cryst. Res. Technol.

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This paper provides a method for improving the photovoltaic conversion efficiency and optical attributes of silicon solar cells manufactured from as‐cut boron doped p‐type multi‐crystalline silicon wafers using acid‐based chemical texturization via machine learning. A decreased reflectance, which can be attained by the right chemical etching conditions, is one of the key elements for raising solar cell efficiency. In this work, the mc‐Silicon wafer surface reflectance is obtained under (<2%) after optimization of wet chemical etching. The HF + HNO3 + CH3COOH chemical etchant is used in the ratio 1:3:2 at different conditions of the etching duration of 1 min, 2 min, 3 min, and 4 min, respectively. The as‐cut boron doped p‐type mc‐silicon wafers are analysed with ultraviolet–visible spectroscopy, optical microscopy, Fourier transforms infrared spectroscopy, thickness profilometer, and scanning electron microscopy before and after etching. The chemical etching solution produces good results in 3 min etched wafer, with a reflectivity value of <2%.The reflectivity and optical images are inputs to the convolutional neural network model and the linear regression model to obtain the etching rate for better reflectivity. The classification model provides 99.6% accuracy and the regression model results in the minimum mean squared error (MSE) of 0.062.

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“…[35] In the overall context, industrial processes such as the chemical etching of silicon wafers by concentrated nitric acid are especially interesting since gas mixtures with an NO content of up to 20 % are produced. [36,37] Owing to the very unsteady evolution of NO, denitrification is particularly difficult by known selective catalytic reduction (SCR) [38] or selective non-catalytic reduction (SNCR) [39] methods. NO fixation and later conversion, as is done in the carbonitrosation protocol, might therefore be a valuable alternative.…”

mentioning

confidence: 99%

Radical Carbonitrosation and Recycling of the Waste Gas Nitrogen Monoxide

Salas

Blank

Heinrich

2011

Chemistry A European J

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HF-HNO3-H2SO4/H2O Mixtures for Etching Multicrystalline Silicon Surfaces: Formation of NO2+, Reaction Rates and Surface Morphologies

Cited by 12 publications

References 0 publications

Passivation and dissolution mechanisms in ordered anodic tantalum oxide nanostructures

Passivation and dissolution mechanisms in ordered anodic tantalum oxide nanostructures

Exploring mc‐Silicon Wafers: Utilizing Machine Learning to Enhance Wafer Quality Through Etching Studies

Radical Carbonitrosation and Recycling of the Waste Gas Nitrogen Monoxide

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