scholarly journals On the Formation of Black Silicon Features by Plasma-Less Etching of Silicon in Molecular Fluorine Gas

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2214
Author(s):  
Bishal Kafle ◽  
Ahmed Ridoy ◽  
Eleni Miethig ◽  
Laurent Clochard ◽  
Edward Duffy ◽  
...  
Keyword(s):  
Silicon Surface ◽  
Elevated Temperatures ◽  
Crystalline Silicon ◽  
High Volume ◽  
Black Silicon ◽  
Gas Mixture ◽  
Process Duration ◽  
Surface Reflection ◽  
Statistical Variation ◽  
Silicon Photovoltaics

In this paper, we study the plasma-less etching of crystalline silicon (c-Si) by F2/N2 gas mixture at moderately elevated temperatures. The etching is performed in an inline etching tool, which is specifically developed to lower costs for products needing a high volume manufacturing etching platform such as silicon photovoltaics. Specifically, the current study focuses on developing an effective front-side texturing process on Si(100) wafers. Statistical variation of the tool parameters is performed to achieve high etching rates and low surface reflection of the textured silicon surface. It is observed that the rate and anisotropy of the etching process are strongly defined by the interaction effects between process parameters such as substrate temperature, F2 concentration, and process duration. The etching forms features of sub-micron dimensions on c-Si surface. By maintaining the anisotropic nature of etching, weighted surface reflection (Rw) as low as Rw < 2% in Si(100) is achievable. The lowering of Rw is mainly due to the formation of deep, density grade nanostructures, so-called black silicon, with lateral dimensions that are smaller to the major wavelength ranges of interest in silicon photovoltaics.

scholarly journals Black silicon quality control by conditions of nickel-assisted etching of crystalline silicon surfaces in photovoltaic devices

2020 ◽  
Vol 60 (1) ◽  
Author(s):  
Mindaugas Kamarauskas ◽  
Marius Treideris ◽  
Vladimir Agafonov ◽  
Audružis Mironas ◽  
Viktorija Strazdienė ◽  
...  
Keyword(s):  
Silicon Surface ◽  
Crystalline Silicon ◽  
Electrochemical Etching ◽  
Photovoltaic Cell ◽  
Silicon Surfaces ◽  
Metal Catalyst ◽  
Black Silicon ◽  
Silicon Substrates ◽  
Photovoltaic Devices ◽  
Thin Nickel

Here we present a study of the nickel-assisted etching applied to form uniform black silicon layers on crystalline silicon substrates. We related the parameters used for technological process control (etchant, nickel thickness) to parameters of the obtained surface and explain the correlation using the etching model responsible for etching of the silicon covered by a thin nickel film. The increase in the thickness of the metal catalyst did not suppress the etching completely but allowed one to tune the roughness of the silicon surface. The rate of the electrochemical etching was additionally changed by adaptation of the proportion of components in the complex etchant. Depending on the intentionally selected conditions, the duration of the optimized process was from 3 to 10 min. The lowest optical reflection commonly accepted as the black silicon surface was obtained for the mixture with a low amount of the active etchant component. It was demonstrated that the method is acceptable to improve the characteristics of a photovoltaic cell.

scholarly journals Effect of Elevated Temperature on Mechanical Properties of High-Volume Fly Ash-Based Geopolymer Concrete, Mortar and Paste Cured at Room Temperature

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1473
Author(s):  
Jun Zhao ◽  
Kang Wang ◽  
Shuaibin Wang ◽  
Zike Wang ◽  
Zhaohui Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperature ◽  
Fly Ash ◽  
Residual Strength ◽  
Elevated Temperatures ◽  
High Volume ◽  
Sem Analysis ◽  
Geopolymer Concrete ◽  
Ordinary Concrete ◽  
Exposure Temperature

This paper presents results from experimental work on mechanical properties of geopolymer concrete, mortar and paste prepared using fly ash and blended slag. Compressive strength, splitting tensile strength and flexural strength tests were conducted on large sets of geopolymer and ordinary concrete, mortar and paste after exposure to elevated temperatures. From Thermogravimetric analyzer (TGA), X-ray diffraction (XRD), Scanning electron microscope (SEM) test results, the geopolymer exhibits excellent resistance to elevated temperature. Compressive strengths of C30, C40 and C50 geopolymer concrete, mortar and paste show incremental improvement then followed by a gradual reduction, and finally reach a relatively consistent value with an increase in exposure temperature. The higher slag content in the geopolymer reduces residual strength and the lower exposure temperature corresponding to peak residual strength. Resistance to elevated temperature of C40 geopolymer concrete, mortar and paste is better than that of ordinary concrete, mortar and paste at the same grade. XRD, TGA and SEM analysis suggests that the heat resistance of C–S–H produced using slag is lower than that of sulphoaluminate gel (quartz and mullite, etc.) produced using fly ash. This facilitates degradation of C30, C40 and C50 geopolymer after exposure to elevated temperatures.

NOHSO4/HF – A Novel Etching System for Crystalline Silicon

2007 ◽  
Vol 62 (11) ◽  
pp. 1411-1421 ◽  
Author(s):  
Sebastian Patzig ◽  
Gerhard Roewer ◽  
Edwin Kroke ◽  
Ingo över
Keyword(s):  
Gas Phase ◽  
Chemical Etching ◽  
Silicon Surface ◽  
Crystalline Silicon ◽  
Etching Solution ◽  
Wide Range ◽  
Ft Ir ◽  
Wet Chemical ◽  
Wet Chemical Etching ◽  
Etching System

Solutions consisting of HF - NOHSO4 - H2SO4 exhibit a strong reactivity towards crystalline silicon which is controlled by the concentrations of the reactive species HF and NO+. Selective isotropic and anisotropic wet chemical etching with these solutions allows to generate a wide range of silicon surface morphology patterns. Traces of Ag+ ions stimulate the reactivity and lead to the formation of planarized (polished) silicon surfaces. Analyses of the silicon surface, the etching solution and the gas phase were performed with scanning electron microscopy (SEM), DR/FT-IR (diffusive reflection Fourier transform infra-red), FT-IR, Raman and NMR spectroscopy, respectively. It was found that the resulting silicon surface is hydrogen-terminated. The gas phase contains predominantly SiF4, NO and N2O. Furthermore, NH4+ is produced in solution. The study has confirmed the crucial role of nitrosyl ions for isotropic wet chemical etching processes. The novel etching system is proposed as an effective new way for selective surface texturing of multi- and monocrystalline silicon. A high etching bath service lifetime, besides a low contamination of the etching solution with reaction products, provides ecological and economical advantages for the semiconductor and solar industry.

Light-soaking enhanced passivation of Al2O3 on crystalline silicon surface

2019 ◽  
Vol 191 ◽  
pp. 350-355 ◽  
Author(s):  
Meng Xie ◽  
Xuegong Yu ◽  
Xiaodong Qiu ◽  
Deren Yang
Keyword(s):  
Silicon Surface ◽  
Crystalline Silicon

scholarly journals Toward a planar black silicon technology for 50 μm-thin crystalline silicon solar cells

2016 ◽  
Vol 24 (18) ◽  
pp. A1224 ◽  
Author(s):  
Jae-Won Song ◽  
Yoon-Ho Nam ◽  
Min-Joon Park ◽  
Bongyoung Yoo ◽  
Jun-Sik Cho ◽  
...  
Keyword(s):  
Solar Cells ◽  
Crystalline Silicon ◽  
Silicon Solar Cells ◽  
Black Silicon ◽  
Crystalline Silicon Solar Cells ◽  
Silicon Technology

Micro- and Nanotextured Silicon for Antireflective Coatings of Solar Cells

2016 ◽  
Vol 39 ◽  
pp. 89-95 ◽  
Author(s):  
Anatoly Druzhinin ◽  
Valery Yerokhov ◽  
Stepan Nichkalo ◽  
Yevhen Berezhanskyi
Keyword(s):  
Solar Cells ◽  
Conversion Efficiency ◽  
Silicon Substrate ◽  
Chemical Etching ◽  
Silicon Surface ◽  
Crystalline Silicon ◽  
Silicon Surfaces ◽  
Antireflective Coatings ◽  
High Conversion Efficiency ◽  
Industrial Use

The paper deals with obtaining of textured silicon surfaces by chemical etching. As a result of experiments based on the modification and optimization of obtaining a textured silicon, several methods of chemical texturing of the crystalline silicon surface were developed. It was shown that modified isotropic and anisotropic etching methods are applicable to create a microrelief on the surface of silicon substrate. These methods in addition to their high conversion efficiency can be used for both mono- and multicrystalline silicon which would ensure their industrial use.

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