Wafer-Scale Fabrication of Ultra-High Aspect Ratio, Microscale Silicon Structures with Smooth Sidewalls Using Metal Assisted Chemical Etching
Silicon structures with ultra-high aspect ratios have great potential applications in the fields of optoelectronics and biomedicine. However, the slope and increased roughness of the sidewalls inevitably introduced during the use of conventional etching processes (e.g., Bosch and DRIE) remain an obs...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-01-01
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| Series: | Micromachines |
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| Online Access: | https://www.mdpi.com/2072-666X/14/1/179 |
| _version_ | 1797438579930038272 |
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| author | Xiaomeng Zhang Chuhao Yao Jiebin Niu Hailiang Li Changqing Xie |
| author_facet | Xiaomeng Zhang Chuhao Yao Jiebin Niu Hailiang Li Changqing Xie |
| author_sort | Xiaomeng Zhang |
| collection | DOAJ |
| description | Silicon structures with ultra-high aspect ratios have great potential applications in the fields of optoelectronics and biomedicine. However, the slope and increased roughness of the sidewalls inevitably introduced during the use of conventional etching processes (e.g., Bosch and DRIE) remain an obstacle to their application. In this paper, 4-inch wafer-scale, ultra-high aspect ratio (>140:1) microscale silicon structures with smooth sidewalls are successfully prepared using metal-assisted chemical etching (MacEtch). Here, we clarify the impact of the size from the metal catalytic structure on the sidewall roughness. By optimizing the etchant ratio to accelerate the etch rate of the metal-catalyzed structure and employing thermal oxidation, the sidewall roughness can be significantly reduced (average root mean square (RMS) from 42.3 nm to 15.8 nm). Simulations show that a maximum exciton production rate (G<sub>max</sub>) of 1.21 × 10<sup>26</sup> and a maximum theoretical short-circuit current density (J<sub>sc</sub>) of 39.78 mA/cm<sup>2</sup> can be obtained for the micropillar array with smooth sidewalls, which have potential applications in high-performance microscale photovoltaic devices. |
| first_indexed | 2024-03-09T11:40:07Z |
| format | Article |
| id | doaj.art-344658b6cdba4f3a841e776e2c7a0f66 |
| institution | Directory Open Access Journal |
| issn | 2072-666X |
| language | English |
| last_indexed | 2024-03-09T11:40:07Z |
| publishDate | 2023-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Micromachines |
| spelling | doaj.art-344658b6cdba4f3a841e776e2c7a0f662023-11-30T23:34:18ZengMDPI AGMicromachines2072-666X2023-01-0114117910.3390/mi14010179Wafer-Scale Fabrication of Ultra-High Aspect Ratio, Microscale Silicon Structures with Smooth Sidewalls Using Metal Assisted Chemical EtchingXiaomeng Zhang0Chuhao Yao1Jiebin Niu2Hailiang Li3Changqing Xie4Key Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029, ChinaKey Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029, ChinaKey Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029, ChinaKey Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029, ChinaKey Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029, ChinaSilicon structures with ultra-high aspect ratios have great potential applications in the fields of optoelectronics and biomedicine. However, the slope and increased roughness of the sidewalls inevitably introduced during the use of conventional etching processes (e.g., Bosch and DRIE) remain an obstacle to their application. In this paper, 4-inch wafer-scale, ultra-high aspect ratio (>140:1) microscale silicon structures with smooth sidewalls are successfully prepared using metal-assisted chemical etching (MacEtch). Here, we clarify the impact of the size from the metal catalytic structure on the sidewall roughness. By optimizing the etchant ratio to accelerate the etch rate of the metal-catalyzed structure and employing thermal oxidation, the sidewall roughness can be significantly reduced (average root mean square (RMS) from 42.3 nm to 15.8 nm). Simulations show that a maximum exciton production rate (G<sub>max</sub>) of 1.21 × 10<sup>26</sup> and a maximum theoretical short-circuit current density (J<sub>sc</sub>) of 39.78 mA/cm<sup>2</sup> can be obtained for the micropillar array with smooth sidewalls, which have potential applications in high-performance microscale photovoltaic devices.https://www.mdpi.com/2072-666X/14/1/179ultra-high aspect ratiomicroscale silicon structuresMacEtchsidewall roughness |
| spellingShingle | Xiaomeng Zhang Chuhao Yao Jiebin Niu Hailiang Li Changqing Xie Wafer-Scale Fabrication of Ultra-High Aspect Ratio, Microscale Silicon Structures with Smooth Sidewalls Using Metal Assisted Chemical Etching Micromachines ultra-high aspect ratio microscale silicon structures MacEtch sidewall roughness |
| title | Wafer-Scale Fabrication of Ultra-High Aspect Ratio, Microscale Silicon Structures with Smooth Sidewalls Using Metal Assisted Chemical Etching |
| title_full | Wafer-Scale Fabrication of Ultra-High Aspect Ratio, Microscale Silicon Structures with Smooth Sidewalls Using Metal Assisted Chemical Etching |
| title_fullStr | Wafer-Scale Fabrication of Ultra-High Aspect Ratio, Microscale Silicon Structures with Smooth Sidewalls Using Metal Assisted Chemical Etching |
| title_full_unstemmed | Wafer-Scale Fabrication of Ultra-High Aspect Ratio, Microscale Silicon Structures with Smooth Sidewalls Using Metal Assisted Chemical Etching |
| title_short | Wafer-Scale Fabrication of Ultra-High Aspect Ratio, Microscale Silicon Structures with Smooth Sidewalls Using Metal Assisted Chemical Etching |
| title_sort | wafer scale fabrication of ultra high aspect ratio microscale silicon structures with smooth sidewalls using metal assisted chemical etching |
| topic | ultra-high aspect ratio microscale silicon structures MacEtch sidewall roughness |
| url | https://www.mdpi.com/2072-666X/14/1/179 |
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