Raman Characterization of Carrier Concentrations of Al-implanted 4H-SiC with Low Carrier Concentration by Photo-Generated Carrier Effect
In this work, 4H SiC samples with a multilayer structure (shallow implanted layer in a lowly doped n-type epitaxial layer grown on a highly doped thick substrate) were investigated by Raman scattering. First, Raman depth profiling was performed to identify characteristic peaks for the different laye...
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MDPI AG
2019-08-01
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| Series: | Crystals |
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| Online Access: | https://www.mdpi.com/2073-4352/9/8/428 |
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| author | Tao Liu Zongwei Xu Mathias Rommel Hong Wang Ying Song Yufang Wang Fengzhou Fang |
| author_facet | Tao Liu Zongwei Xu Mathias Rommel Hong Wang Ying Song Yufang Wang Fengzhou Fang |
| author_sort | Tao Liu |
| collection | DOAJ |
| description | In this work, 4H SiC samples with a multilayer structure (shallow implanted layer in a lowly doped n-type epitaxial layer grown on a highly doped thick substrate) were investigated by Raman scattering. First, Raman depth profiling was performed to identify characteristic peaks for the different layers. Then, Raman scattering was used to characterize the carrier concentration of the samples. In contrast to the conventional Raman scattering measuring method of the Longitudinal Optical Plasmon Coupled (LOPC) mode, which is only suitable to characterize carrier concentrations in the range from 2 × 10<sup>16</sup> to 5 × 10<sup>18</sup> cm<sup>−3</sup>, in this work, Raman scattering, which is based on exciting photons with an energy above the band gap of 4H-SiC, was used. The proposed method was evaluated and approved for different Al-implanted samples. It was found that with increasing laser power the Al-implanted layers lead to a consistent redshift of the LOPC Raman peak compared to the peak of the non-implanted layer, which might be explained by a consistent change in effective photo-generated carrier concentration. Besides, it could be demonstrated that the lower concentration limit of the conventional approach can be extended to a value of 5 × 10<sup>15</sup> cm<sup>−3</sup> with the approach presented here. |
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| last_indexed | 2024-04-13T08:25:43Z |
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| series | Crystals |
| spelling | doaj.art-83aee7bda3de46f991bcf7360f0d43192022-12-22T02:54:30ZengMDPI AGCrystals2073-43522019-08-019842810.3390/cryst9080428cryst9080428Raman Characterization of Carrier Concentrations of Al-implanted 4H-SiC with Low Carrier Concentration by Photo-Generated Carrier EffectTao Liu0Zongwei Xu1Mathias Rommel2Hong Wang3Ying Song4Yufang Wang5Fengzhou Fang6State Key Laboratory of Precision Measuring Technology & Instruments, Centre of Micro/Nano Manufacturing Technology, Tianjin University, Tianjin 300072, ChinaState Key Laboratory of Precision Measuring Technology & Instruments, Centre of Micro/Nano Manufacturing Technology, Tianjin University, Tianjin 300072, ChinaFraunhofer Institute for Integrated Systems and Device Technology IISB, Schottkystrasse 10, 91058 Erlangen, GermanyState Key Laboratory of Separation Membranes and Membrane Processes, School of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin 300387, ChinaState Key Laboratory of Precision Measuring Technology & Instruments, Centre of Micro/Nano Manufacturing Technology, Tianjin University, Tianjin 300072, ChinaSchool of Physics, Nankai University, Tianjin 300071, ChinaState Key Laboratory of Precision Measuring Technology & Instruments, Centre of Micro/Nano Manufacturing Technology, Tianjin University, Tianjin 300072, ChinaIn this work, 4H SiC samples with a multilayer structure (shallow implanted layer in a lowly doped n-type epitaxial layer grown on a highly doped thick substrate) were investigated by Raman scattering. First, Raman depth profiling was performed to identify characteristic peaks for the different layers. Then, Raman scattering was used to characterize the carrier concentration of the samples. In contrast to the conventional Raman scattering measuring method of the Longitudinal Optical Plasmon Coupled (LOPC) mode, which is only suitable to characterize carrier concentrations in the range from 2 × 10<sup>16</sup> to 5 × 10<sup>18</sup> cm<sup>−3</sup>, in this work, Raman scattering, which is based on exciting photons with an energy above the band gap of 4H-SiC, was used. The proposed method was evaluated and approved for different Al-implanted samples. It was found that with increasing laser power the Al-implanted layers lead to a consistent redshift of the LOPC Raman peak compared to the peak of the non-implanted layer, which might be explained by a consistent change in effective photo-generated carrier concentration. Besides, it could be demonstrated that the lower concentration limit of the conventional approach can be extended to a value of 5 × 10<sup>15</sup> cm<sup>−3</sup> with the approach presented here.https://www.mdpi.com/2073-4352/9/8/428Raman spectroscopysilicon carbideLOPC (Longitudinal Optical Plasmon Coupled) modecarrier concentrationphoto-generated carriers |
| spellingShingle | Tao Liu Zongwei Xu Mathias Rommel Hong Wang Ying Song Yufang Wang Fengzhou Fang Raman Characterization of Carrier Concentrations of Al-implanted 4H-SiC with Low Carrier Concentration by Photo-Generated Carrier Effect Crystals Raman spectroscopy silicon carbide LOPC (Longitudinal Optical Plasmon Coupled) mode carrier concentration photo-generated carriers |
| title | Raman Characterization of Carrier Concentrations of Al-implanted 4H-SiC with Low Carrier Concentration by Photo-Generated Carrier Effect |
| title_full | Raman Characterization of Carrier Concentrations of Al-implanted 4H-SiC with Low Carrier Concentration by Photo-Generated Carrier Effect |
| title_fullStr | Raman Characterization of Carrier Concentrations of Al-implanted 4H-SiC with Low Carrier Concentration by Photo-Generated Carrier Effect |
| title_full_unstemmed | Raman Characterization of Carrier Concentrations of Al-implanted 4H-SiC with Low Carrier Concentration by Photo-Generated Carrier Effect |
| title_short | Raman Characterization of Carrier Concentrations of Al-implanted 4H-SiC with Low Carrier Concentration by Photo-Generated Carrier Effect |
| title_sort | raman characterization of carrier concentrations of al implanted 4h sic with low carrier concentration by photo generated carrier effect |
| topic | Raman spectroscopy silicon carbide LOPC (Longitudinal Optical Plasmon Coupled) mode carrier concentration photo-generated carriers |
| url | https://www.mdpi.com/2073-4352/9/8/428 |
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