Interaction Energy Dependency on Pulse Width in ns NIR Laser Scanning of Silicon
Laser ablation of semiconductor silicon has been extensively studied in the past few decades. In the ultrashort pulse domain, whether in the fs scale or ps scale, the pulse energy fluence threshold in the ablation of silicon is strongly dependent on the pulse width. However, in the ns pulse scale, t...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-12-01
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| Series: | Micromachines |
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| Online Access: | https://www.mdpi.com/2072-666X/14/1/119 |
| _version_ | 1797438588384706560 |
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| author | Shunping Li Xinchang Wang Guojie Chen Zhongke Wang |
| author_facet | Shunping Li Xinchang Wang Guojie Chen Zhongke Wang |
| author_sort | Shunping Li |
| collection | DOAJ |
| description | Laser ablation of semiconductor silicon has been extensively studied in the past few decades. In the ultrashort pulse domain, whether in the fs scale or ps scale, the pulse energy fluence threshold in the ablation of silicon is strongly dependent on the pulse width. However, in the ns pulse scale, the energy fluence threshold dependence on the pulse width is not well understood. This study elucidates the interaction energy dependency on pulse width in ns NIR laser ablation of silicon. The level of ablation or melting was determined by the pulse energy deposition rate, which was proportional to laser peak power. Shorter pulse widths with high peak power were likely to induce surface ablation, while longer pulse widths were likely to induce surface melting. The ablation threshold increased from 5.63 to 24.84 J/cm<sup>2</sup> as the pulse width increased from 26 to 500 ns. The melting threshold increased from 3.33 to 5.76 J/cm<sup>2</sup> as the pulse width increased from 26 to 200 ns, and then remained constant until 500 ns, the longest width investigated. Distinct from a shorter pulse width, a longer pulse width did not require a higher power level for inducing surface melting, as surface melting can be induced at a lower power with the longer heating time of a longer pulse width. The line width from surface melting was less than the focused spot size; the line appeared either as a continuous line at slow scanning speed or as isolated dots at high scanning speed. In contrast, the line width from ablation significantly exceeded the focused spot size. |
| first_indexed | 2024-03-09T11:40:14Z |
| format | Article |
| id | doaj.art-5c46244ca5ce41f49af9889f5807beb4 |
| institution | Directory Open Access Journal |
| issn | 2072-666X |
| language | English |
| last_indexed | 2024-03-09T11:40:14Z |
| publishDate | 2022-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Micromachines |
| spelling | doaj.art-5c46244ca5ce41f49af9889f5807beb42023-11-30T23:33:28ZengMDPI AGMicromachines2072-666X2022-12-0114111910.3390/mi14010119Interaction Energy Dependency on Pulse Width in ns NIR Laser Scanning of SiliconShunping Li0Xinchang Wang1Guojie Chen2Zhongke Wang3Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528220, ChinaGuangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528220, ChinaGuangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528220, ChinaSingapore Institute of Manufacturing Technology (SIMTech), A*Star, 2 Fusionopolis Way, Singapore 138634, SingaporeLaser ablation of semiconductor silicon has been extensively studied in the past few decades. In the ultrashort pulse domain, whether in the fs scale or ps scale, the pulse energy fluence threshold in the ablation of silicon is strongly dependent on the pulse width. However, in the ns pulse scale, the energy fluence threshold dependence on the pulse width is not well understood. This study elucidates the interaction energy dependency on pulse width in ns NIR laser ablation of silicon. The level of ablation or melting was determined by the pulse energy deposition rate, which was proportional to laser peak power. Shorter pulse widths with high peak power were likely to induce surface ablation, while longer pulse widths were likely to induce surface melting. The ablation threshold increased from 5.63 to 24.84 J/cm<sup>2</sup> as the pulse width increased from 26 to 500 ns. The melting threshold increased from 3.33 to 5.76 J/cm<sup>2</sup> as the pulse width increased from 26 to 200 ns, and then remained constant until 500 ns, the longest width investigated. Distinct from a shorter pulse width, a longer pulse width did not require a higher power level for inducing surface melting, as surface melting can be induced at a lower power with the longer heating time of a longer pulse width. The line width from surface melting was less than the focused spot size; the line appeared either as a continuous line at slow scanning speed or as isolated dots at high scanning speed. In contrast, the line width from ablation significantly exceeded the focused spot size.https://www.mdpi.com/2072-666X/14/1/119silicon waferpulse widthlaser ablationablation thresholdsurface melting |
| spellingShingle | Shunping Li Xinchang Wang Guojie Chen Zhongke Wang Interaction Energy Dependency on Pulse Width in ns NIR Laser Scanning of Silicon Micromachines silicon wafer pulse width laser ablation ablation threshold surface melting |
| title | Interaction Energy Dependency on Pulse Width in ns NIR Laser Scanning of Silicon |
| title_full | Interaction Energy Dependency on Pulse Width in ns NIR Laser Scanning of Silicon |
| title_fullStr | Interaction Energy Dependency on Pulse Width in ns NIR Laser Scanning of Silicon |
| title_full_unstemmed | Interaction Energy Dependency on Pulse Width in ns NIR Laser Scanning of Silicon |
| title_short | Interaction Energy Dependency on Pulse Width in ns NIR Laser Scanning of Silicon |
| title_sort | interaction energy dependency on pulse width in ns nir laser scanning of silicon |
| topic | silicon wafer pulse width laser ablation ablation threshold surface melting |
| url | https://www.mdpi.com/2072-666X/14/1/119 |
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