Texturing of SiC-slurry and diamond wire sawn silicon wafers by HF–HNO3–H2SO4 mixtures

Lippold, Marcus; Buchholz, Florian; Gondek, Christoph; Honeit, Florian; Wefringhaus, E.; Kroke, Edwin

doi:10.1016/j.solmat.2014.04.006

Cited by 58 publications

(21 citation statements)

References 24 publications

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“…Wet‐chemical treatment of silicon wafers is used for saw damage removal surface cleaning polishing and texturing of wafer surfaces as well as recycling of silicon materials . The texturization is of relevance in photovoltaics in order to increase the light‐trapping efficiency.…”

Section: Introductionmentioning

confidence: 99%

Etching SiC‐slurry and diamond wire‐sawn silicon wafers with HF‐HCl‐Cl₂ mixtures: Parameter influences on etch rates and surface structures

Stapf

Nattrodt

Gondek

et al. 2017

Physica Status Solidi (a)

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Solutions for the wet chemical treatment of silicon wafer surfaces were investigated using mixtures which are based on hydrofluoric acid (HF), hydrochloric acid (HCl), and chlorine (Cl 2 ). We used a DoE-test plan (Design of Experiments) to evaluate the effects of five selected parameters: concentrations of HF and HCl, gas flow rate of Cl 2 , stirring, and saw type of the wafer material. High etch rates of up to 0.63 mm min À1 were observed at room temperature, which are comparable to the etch rates of KOH-IPA solutions. The silicon surface was investigated by reflectivity measurements and scanning electron microscopy (SEM), indicating pyramidal textured and polished surfaces for diamond wireand SiC-slurry-sawn wafers. Using an optimized parameter set, random inverted pyramidal surface structures are formed. These random inverted structures show a significant increase in light absorption compared to standard random upright pyramid textures, for example produced by KOH-IPA solutions.

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Section: Introductionmentioning

confidence: 99%

Etching SiC‐slurry and diamond wire‐sawn silicon wafers with HF‐HCl‐Cl₂ mixtures: Parameter influences on etch rates and surface structures

Stapf

Nattrodt

Gondek

et al. 2017

Physica Status Solidi (a)

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“…Various additives, such as CH 3 COOH, H 3 PO 4 , H 2 SO 4 , or HCl influence the reactivity toward silicon, surface morphologies, and the cleaning efficiency. [9][10][11][12] The dissolution of silicon in hydrofluoric acid-based mixtures is basically described as a process of two subsequent steps. The oxidation of silicon (Equation 1) is followed by the complexation of the oxidized silicon species by fluoride ions in order to form SiF 6 2− (Equation 2).…”

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confidence: 99%

On The Mechanism of the Anisotropic Dissolution of Silicon in Chlorine Containing Hydrofluoric Acid Solutions

Stapf

Nattrodt

Kroke

2017

J. Electrochem. Soc.

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The wet-chemical acidic treatment of silicon wafer surfaces is very important in photovoltaic, microelectronic and further industries. Recent works report on new mixtures for acidic anisotropic etching mixtures based on hydrofluoric acid HF and hydrochloric acid HCl with an added oxidant. The aim of this work was to get an insight into the reactions during the etching process of silicon in the system HF-HCl-Cl 2 . The etching mixtures, gaseous reaction products, as well as the generated silicon surfaces were investigated by 19 F, 29 Si, and 35 Cl NMR, ion chromatography (IC), iodometric titration, FT-IR spectroscopy, diffuse reflectance FT-IR spectroscopy (DRIFT) as well as scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDX). A reaction scheme for the anisotropic dissolution of silicon in chlorine containing aqueous HF-solutions is proposed, which involves dissolved Cl 2 as the oxidizing agent, coordination of fluoride/chloride ions and formation of a hydrophilic surface. These steps are similar to the well known alkaline anisotropic etching of silicon.

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“…In the last few years, the wafer manufacturing industry moved from regular slurry wire cut (SWC) to diamond wire cut wafers (DWC) considering the potential savings in silicon material wastage and significant improvement in sawing process throughput [6] [7] [8]. This created a cost pressure on solar cell manufacturers to quickly adapt to the changes in surface morphology of incoming diamond wire cut wafers as compared to slurry cut wafers and re-optimize the acidic etchant bath to deliver same quality of texturing process [9]. Establishment of a standard texturing process plays a key role in producing a wafer surface of diamond wire cut wafers that is equal or better to slurry cut wafers in terms of kerf loss, total thickness variation, reflectivity, mechanical strength and wafer performance for solar cells [10].…”

Section: Introductionmentioning

confidence: 99%

Challenges in Processing Diamond Wire Cut and Black Silicon Wafers in Large-Scale Manufacturing of High Efficiency Solar Cells

Shetty¹,

Kaushal²,

Chikkan³

et al. 2020

JPEE

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Texturing of diamond wire cut wafers using a standard wafer etch process chemistry has always been a challenge in solar cell manufacturing industry. This is due to the change in surface morphology of diamond wire cut wafers and the abundant presence of amorphous silicon content, which are introduced from wafer manufacturing industry during sawing of multi-crystalline wafers using ultra-thin diamond wires. The industry standard texturing process for multi-crystalline wafers cannot deliver a homogeneous etched silicon surface, thereby requiring an additive compound, which acts like a surfactant in the acidic etch bath to enhance the texturing quality on diamond wire cut wafers. Black silicon wafers on the other hand require completely a different process chemistry and are normally textured using a metal catalyst assisted etching technique or by plasma reactive ion etching technique. In this paper, various challenges associated with cell processing steps using diamond wire cut and black silicon wafers along with cell electrical results using each of these wafer types are discussed.

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Texturing of SiC-slurry and diamond wire sawn silicon wafers by HF–HNO3–H2SO4 mixtures

Cited by 58 publications

References 24 publications

Etching SiC‐slurry and diamond wire‐sawn silicon wafers with HF‐HCl‐Cl₂ mixtures: Parameter influences on etch rates and surface structures

Etching SiC‐slurry and diamond wire‐sawn silicon wafers with HF‐HCl‐Cl₂ mixtures: Parameter influences on etch rates and surface structures

On The Mechanism of the Anisotropic Dissolution of Silicon in Chlorine Containing Hydrofluoric Acid Solutions

Challenges in Processing Diamond Wire Cut and Black Silicon Wafers in Large-Scale Manufacturing of High Efficiency Solar Cells

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Texturing of SiC-slurry and diamond wire sawn silicon wafers by HF–HNO3–H2SO4 mixtures

Cited by 58 publications

References 24 publications

Etching SiC‐slurry and diamond wire‐sawn silicon wafers with HF‐HCl‐Cl2 mixtures: Parameter influences on etch rates and surface structures

Etching SiC‐slurry and diamond wire‐sawn silicon wafers with HF‐HCl‐Cl2 mixtures: Parameter influences on etch rates and surface structures

On The Mechanism of the Anisotropic Dissolution of Silicon in Chlorine Containing Hydrofluoric Acid Solutions

Challenges in Processing Diamond Wire Cut and Black Silicon Wafers in Large-Scale Manufacturing of High Efficiency Solar Cells

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Etching SiC‐slurry and diamond wire‐sawn silicon wafers with HF‐HCl‐Cl₂ mixtures: Parameter influences on etch rates and surface structures

Etching SiC‐slurry and diamond wire‐sawn silicon wafers with HF‐HCl‐Cl₂ mixtures: Parameter influences on etch rates and surface structures