The Method of Low-Temperature ICP Etching of InP/InGaAsP Heterostructures in Cl<sub>2</sub>-Based Plasma for Integrated Optics Applications
Chlorine processes are widely used for the formation of waveguide structures in InP-based optoelectronics. Traditionally, ICP etching of InP in a Cl<sub>2</sub>-based plasma requires substrate temperatures in the range of 150–200 °C. This condition is mandatory, since during the etching...
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MDPI AG
2021-12-01
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| Online Access: | https://www.mdpi.com/2072-666X/12/12/1535 |
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| author | Sergey Ishutkin Vadim Arykov Igor Yunusov Mikhail Stepanenko Vyacheslav Smirnov Pavel Troyan Yury Zhidik |
| author_facet | Sergey Ishutkin Vadim Arykov Igor Yunusov Mikhail Stepanenko Vyacheslav Smirnov Pavel Troyan Yury Zhidik |
| author_sort | Sergey Ishutkin |
| collection | DOAJ |
| description | Chlorine processes are widely used for the formation of waveguide structures in InP-based optoelectronics. Traditionally, ICP etching of InP in a Cl<sub>2</sub>-based plasma requires substrate temperatures in the range of 150–200 °C. This condition is mandatory, since during the etching process low-volatility InCl<sub>x</sub> components are formed and at insufficient temperatures are deposited onto substrate, leading to the formation of defects and further impossibility of the formation of waveguide structures. The need to preheat the substrate limits the application of chlorine processes. This paper presents a method of ICP etching an InP/InGaAsP heterostructure in a Cl<sub>2</sub>/Ar/N<sub>2</sub> gas mixture. A feature of the developed method is the cyclic etching of the heterostructure without preliminary heating. The etching process starts at room temperature. In the optimal etching mode, the angle of inclination of the sidewalls of the waveguides reached 88.8° at an etching depth of more than 4.5 μm. At the same time, the surface roughness did not exceed 30 nm. The selectivity of the etching process with respect to the SiN<sub>x</sub> mask was equal to 9. Using the developed etching method, test integrated waveguide elements were fabricated. The fabricated active integrated waveguide (p-InP epitaxial layers were not removed) with a width of 2 μm demonstrated an optical loss around 11 ± 1.5 dB/cm at 1550 nm. The insertion loss of the developed Y- and MMI-splitters did not exceed 0.8 dB. |
| first_indexed | 2024-03-10T03:33:20Z |
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| id | doaj.art-83484746c14b4089bbba81861dddbb0a |
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| language | English |
| last_indexed | 2024-03-10T03:33:20Z |
| publishDate | 2021-12-01 |
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| series | Micromachines |
| spelling | doaj.art-83484746c14b4089bbba81861dddbb0a2023-11-23T09:36:42ZengMDPI AGMicromachines2072-666X2021-12-011212153510.3390/mi12121535The Method of Low-Temperature ICP Etching of InP/InGaAsP Heterostructures in Cl<sub>2</sub>-Based Plasma for Integrated Optics ApplicationsSergey Ishutkin0Vadim Arykov1Igor Yunusov2Mikhail Stepanenko3Vyacheslav Smirnov4Pavel Troyan5Yury Zhidik6Micran, Research and Production Company, 634041 Tomsk, RussiaIntegrated Optics and Microwave Photonics Laboratory, Tomsk State University of Control System and Radioelectronics, 634050 Tomsk, RussiaIntegrated Optics and Microwave Photonics Laboratory, Tomsk State University of Control System and Radioelectronics, 634050 Tomsk, RussiaIntegrated Optics and Microwave Photonics Laboratory, Tomsk State University of Control System and Radioelectronics, 634050 Tomsk, RussiaMicran, Research and Production Company, 634041 Tomsk, RussiaIntegrated Optics and Microwave Photonics Laboratory, Tomsk State University of Control System and Radioelectronics, 634050 Tomsk, RussiaIntegrated Optics and Microwave Photonics Laboratory, Tomsk State University of Control System and Radioelectronics, 634050 Tomsk, RussiaChlorine processes are widely used for the formation of waveguide structures in InP-based optoelectronics. Traditionally, ICP etching of InP in a Cl<sub>2</sub>-based plasma requires substrate temperatures in the range of 150–200 °C. This condition is mandatory, since during the etching process low-volatility InCl<sub>x</sub> components are formed and at insufficient temperatures are deposited onto substrate, leading to the formation of defects and further impossibility of the formation of waveguide structures. The need to preheat the substrate limits the application of chlorine processes. This paper presents a method of ICP etching an InP/InGaAsP heterostructure in a Cl<sub>2</sub>/Ar/N<sub>2</sub> gas mixture. A feature of the developed method is the cyclic etching of the heterostructure without preliminary heating. The etching process starts at room temperature. In the optimal etching mode, the angle of inclination of the sidewalls of the waveguides reached 88.8° at an etching depth of more than 4.5 μm. At the same time, the surface roughness did not exceed 30 nm. The selectivity of the etching process with respect to the SiN<sub>x</sub> mask was equal to 9. Using the developed etching method, test integrated waveguide elements were fabricated. The fabricated active integrated waveguide (p-InP epitaxial layers were not removed) with a width of 2 μm demonstrated an optical loss around 11 ± 1.5 dB/cm at 1550 nm. The insertion loss of the developed Y- and MMI-splitters did not exceed 0.8 dB.https://www.mdpi.com/2072-666X/12/12/1535ICP etchingwaveguidesInPcyclic etchingplasma polishing |
| spellingShingle | Sergey Ishutkin Vadim Arykov Igor Yunusov Mikhail Stepanenko Vyacheslav Smirnov Pavel Troyan Yury Zhidik The Method of Low-Temperature ICP Etching of InP/InGaAsP Heterostructures in Cl<sub>2</sub>-Based Plasma for Integrated Optics Applications Micromachines ICP etching waveguides InP cyclic etching plasma polishing |
| title | The Method of Low-Temperature ICP Etching of InP/InGaAsP Heterostructures in Cl<sub>2</sub>-Based Plasma for Integrated Optics Applications |
| title_full | The Method of Low-Temperature ICP Etching of InP/InGaAsP Heterostructures in Cl<sub>2</sub>-Based Plasma for Integrated Optics Applications |
| title_fullStr | The Method of Low-Temperature ICP Etching of InP/InGaAsP Heterostructures in Cl<sub>2</sub>-Based Plasma for Integrated Optics Applications |
| title_full_unstemmed | The Method of Low-Temperature ICP Etching of InP/InGaAsP Heterostructures in Cl<sub>2</sub>-Based Plasma for Integrated Optics Applications |
| title_short | The Method of Low-Temperature ICP Etching of InP/InGaAsP Heterostructures in Cl<sub>2</sub>-Based Plasma for Integrated Optics Applications |
| title_sort | method of low temperature icp etching of inp ingaasp heterostructures in cl sub 2 sub based plasma for integrated optics applications |
| topic | ICP etching waveguides InP cyclic etching plasma polishing |
| url | https://www.mdpi.com/2072-666X/12/12/1535 |
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