Texturing of monocrystalline silicon wafers by HF-HCl-H2O2 mixtures: Generation of random inverted pyramids and simulation of light trapping in PERC solar cells

Stapf, André; Honeit, Florian; Gondek, Christoph; Kroke, Edwin

doi:10.1016/j.solmat.2016.08.034

Cited by 42 publications

(14 citation statements)

References 18 publications

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“…The random inverted pyramidal texture shows a significant decrease of the reflected incoming light. As it was already shown by simulations, this structure has better properties with regard to light trapping efficiency compared to the conventional random pyramid structures generated by KOH‐IPA‐solutions .…”

Section: Resultssupporting

confidence: 54%

“…We recently examined acidic mixtures based on hydrofluoric and hydrochloric acid with added oxidants for the generation of pyramidal structures on monocrystalline (100) wafers. The investigated oxidizing agents include ammonium persulfate ((NH 4 ) 2 S 2 O 8 ) , hydrogen peroxide (H 2 O 2 ) , and ozone (O 3 ) . In these mixtures, chlorine (Cl 2 ) and trichloride ions (Cl 3 − ) are formed by the oxidation of the chloride ions contained in the hydrochloric acid by the respective oxidizing agent (Eqs.…”

Section: Introductionmentioning

confidence: 99%

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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

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: Resultssupporting

confidence: 54%

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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“…The PCE of a silicon cell can be improved in two basic ways: (1) Increasing its sunlight absorption rate and (2) enhancing its PV effect [2,3]. A pyramidal trapping texture is directly prepared on the surface of a silicon wafer by chemical texturing, which can effectively improve the sunlight absorption rate, thereby improving the PCE [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Standard Deviation Quantitative Characterization and Process Optimization of the Pyramidal Texture of Monocrystalline Silicon Cells

Fang

Jang

et al. 2020

Materials

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To quantitatively characterize the pyramidal texture of monocrystalline silicon cells and to optimize the parameters of the texturing process, the relative standard deviation Sh was proposed to quantitatively characterize the uniformity of the pyramidal texture. Referring to the definition and calculation of the standard deviation in mathematical statistics, Sh was defined as the standard deviation of the pyramid relative height hi after normalization of the pyramid height Hi of monocrystalline silicon wafer surfaces. Six different silicon cells, with different pyramidal textures, were obtained by applying different texturing times. The relationships between Sh and the photoelectric characteristics were analyzed. The feasibility of quantitatively characterizing the uniformity of the pyramidal texture using Sh was verified. By fitting the Sh curve, the feasibility of optimizing the texturing process parameters and predicting the photoelectric characteristics using Sh was verified. The experimental and analytical results indicate that, when the relative standard deviation Sh was smaller, the uniformity of the pyramidal texture obtained by texturing was better. The photoelectric conversion efficiency (PCE) of the silicon cells monotonically increased with decreasing Sh. The silicon cell obtained by texturing with 2% tetramethylammonium hydroxide (TMAH) solution for 18.1 min had a textured surface with a minimum of Sh, the reflectivity of the silicon cell reached its minimum value of 2.28%, and the PCE reached its maximum value of 19.76%.

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“…Research on the chemical processes for SDR has focused on the use of HCl-H 2 O 2 mixtures [10], KOH-or NaOH-based solutions, HF-HNO 3 mixtures [5,11], and HF-or HCl-based solutions [12], but these have not proved effective in achieving complete removal of saw marks. To solve this problem, a mixture of KOH and NaOCl was employed and favorable results were achieved in another study [3].…”

Section: Introductionmentioning

confidence: 99%

Pre-Texturing Thermal Treatment for Saw-Damage-Removal-Free Wet Texturing of Monocrystalline Silicon Wafers

et al. 2020

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The etching of Si wafers significantly influences the efficiency of photovoltaic devices. Texturing can effectively decrease front surface reflection and improve device performance. Saw damage removal (SDR) is necessary to yields uniform random pyramidal surfaces without the appearance of saw marks, it entails significant consumption of chemical solutions and complicated cleaning steps. Herein, an alternative process of pre-texturing thermal treatment was carried out at 800 °C for 10 min, followed by anisotropic texturing, and a uniform pyramidal surface over a large area of the textured surface was obtained without saw marks. Compared with that of as-cut mono-Si wafers (30.7%), the weighted average reflectance of the samples textured with or without thermal treatment decreased to 11.2% and 11.9%, respectively, and further to 3% and 3.4%, respectively, when anti-reflection coatings were applied. In addition, saw marks on the wafer surface were used as gettering sites during thermal treatment, and the bulk lifetime was more than doubled from 42.6 µs before the treatment to 93.8 µs after. The simple, SDR-free method presented herein for enhancing the textural uniformity of Si wafers and, hence, solar cell performance, can be employed on an industrial scale without necessitating additional investment in equipment.

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Texturing of monocrystalline silicon wafers by HF-HCl-H2O2 mixtures: Generation of random inverted pyramids and simulation of light trapping in PERC solar cells

Cited by 42 publications

References 18 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

Standard Deviation Quantitative Characterization and Process Optimization of the Pyramidal Texture of Monocrystalline Silicon Cells

Pre-Texturing Thermal Treatment for Saw-Damage-Removal-Free Wet Texturing of Monocrystalline Silicon Wafers

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Texturing of monocrystalline silicon wafers by HF-HCl-H2O2 mixtures: Generation of random inverted pyramids and simulation of light trapping in PERC solar cells

Cited by 42 publications

References 18 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

Standard Deviation Quantitative Characterization and Process Optimization of the Pyramidal Texture of Monocrystalline Silicon Cells

Pre-Texturing Thermal Treatment for Saw-Damage-Removal-Free Wet Texturing of Monocrystalline Silicon Wafers

Contact Info

Product

Resources

About

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