On the Formation of Black Silicon Features by Plasma-Less Etching of Silicon in Molecular Fluorine Gas
In this paper, we study the plasma-less etching of crystalline silicon (c-Si) by F<sub>2</sub>/N<sub>2</sub> gas mixture at moderately elevated temperatures. The etching is performed in an inline etching tool, which is specifically developed to lower costs for products needin...
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| Format: | Article |
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MDPI AG
2020-11-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/10/11/2214 |
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| author | Bishal Kafle Ahmed Ismail Ridoy Eleni Miethig Laurent Clochard Edward Duffy Marc Hofmann Jochen Rentsch |
| author_facet | Bishal Kafle Ahmed Ismail Ridoy Eleni Miethig Laurent Clochard Edward Duffy Marc Hofmann Jochen Rentsch |
| author_sort | Bishal Kafle |
| collection | DOAJ |
| description | In this paper, we study the plasma-less etching of crystalline silicon (c-Si) by F<sub>2</sub>/N<sub>2</sub> 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, F<sub>2</sub> 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 (<i>R</i><sub>w</sub>) as low as <i>R</i><sub>w</sub> < 2% in Si(100) is achievable. The lowering of <i>R</i><sub>w</sub> 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. |
| first_indexed | 2024-03-10T15:02:12Z |
| format | Article |
| id | doaj.art-7add3fbd956c456fa20f3b9dc1d4f6ba |
| institution | Directory Open Access Journal |
| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-10T15:02:12Z |
| publishDate | 2020-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Nanomaterials |
| spelling | doaj.art-7add3fbd956c456fa20f3b9dc1d4f6ba2023-11-20T20:04:46ZengMDPI AGNanomaterials2079-49912020-11-011011221410.3390/nano10112214On the Formation of Black Silicon Features by Plasma-Less Etching of Silicon in Molecular Fluorine GasBishal Kafle0Ahmed Ismail Ridoy1Eleni Miethig2Laurent Clochard3Edward Duffy4Marc Hofmann5Jochen Rentsch6Fraunhofer Institute for Solar Energy Systems (ISE), 79110 Freiburg im Breisgau, GermanyFraunhofer Institute for Solar Energy Systems (ISE), 79110 Freiburg im Breisgau, GermanyFraunhofer Institute for Solar Energy Systems (ISE), 79110 Freiburg im Breisgau, GermanyNines Photovoltaics, Dublin 24, IrelandNines Photovoltaics, Dublin 24, IrelandFraunhofer Institute for Solar Energy Systems (ISE), 79110 Freiburg im Breisgau, GermanyFraunhofer Institute for Solar Energy Systems (ISE), 79110 Freiburg im Breisgau, GermanyIn this paper, we study the plasma-less etching of crystalline silicon (c-Si) by F<sub>2</sub>/N<sub>2</sub> 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, F<sub>2</sub> 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 (<i>R</i><sub>w</sub>) as low as <i>R</i><sub>w</sub> < 2% in Si(100) is achievable. The lowering of <i>R</i><sub>w</sub> 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.https://www.mdpi.com/2079-4991/10/11/2214dry etchingblack siliconphotovoltaics |
| spellingShingle | Bishal Kafle Ahmed Ismail Ridoy Eleni Miethig Laurent Clochard Edward Duffy Marc Hofmann Jochen Rentsch On the Formation of Black Silicon Features by Plasma-Less Etching of Silicon in Molecular Fluorine Gas Nanomaterials dry etching black silicon photovoltaics |
| title | On the Formation of Black Silicon Features by Plasma-Less Etching of Silicon in Molecular Fluorine Gas |
| title_full | On the Formation of Black Silicon Features by Plasma-Less Etching of Silicon in Molecular Fluorine Gas |
| title_fullStr | On the Formation of Black Silicon Features by Plasma-Less Etching of Silicon in Molecular Fluorine Gas |
| title_full_unstemmed | On the Formation of Black Silicon Features by Plasma-Less Etching of Silicon in Molecular Fluorine Gas |
| title_short | On the Formation of Black Silicon Features by Plasma-Less Etching of Silicon in Molecular Fluorine Gas |
| title_sort | on the formation of black silicon features by plasma less etching of silicon in molecular fluorine gas |
| topic | dry etching black silicon photovoltaics |
| url | https://www.mdpi.com/2079-4991/10/11/2214 |
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