Defect Passivation and Carrier Reduction Mechanisms in Hydrogen-Doped In-Ga-Zn-O (IGZO:H) Films upon Low-Temperature Annealing for Flexible Device Applications
Low-temperature activation of oxide semiconductor materials such as In-Ga-Zn-O (IGZO) is a key approach for their utilization in flexible devices. We previously reported that the activation temperature can be reduced to 150 °C by hydrogen-doped IGZO (IGZO:H), demonstrating a strong potential of this...
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MDPI AG
2022-01-01
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| Online Access: | https://www.mdpi.com/1996-1944/15/1/334 |
| _version_ | 1797498387360120832 |
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| author | Rostislav Velichko Yusaku Magari Mamoru Furuta |
| author_facet | Rostislav Velichko Yusaku Magari Mamoru Furuta |
| author_sort | Rostislav Velichko |
| collection | DOAJ |
| description | Low-temperature activation of oxide semiconductor materials such as In-Ga-Zn-O (IGZO) is a key approach for their utilization in flexible devices. We previously reported that the activation temperature can be reduced to 150 °C by hydrogen-doped IGZO (IGZO:H), demonstrating a strong potential of this approach. In this paper, we investigated the mechanism for reducing the activation temperature of the IGZO:H films. In situ Hall measurements revealed that oxygen diffusion from annealing ambient into the conventional Ar/O<sub>2</sub>-sputtered IGZO film was observed at >240 °C. Moreover, the temperature at which the oxygen diffusion starts into the film significantly decreased to 100 °C for the IGZO:H film deposited at hydrogen gas flow ratio (R[H<sub>2</sub>]) of 8%. Hard X-ray photoelectron spectroscopy indicated that the near Fermi level (E<sub>F</sub>) defects in the IGZO:H film after the 150 °C annealing decreased in comparison to that in the conventional IGZO film after 300 °C annealing. The oxygen diffusion into the film during annealing plays an important role for reducing oxygen vacancies and subgap states especially for near E<sub>F</sub>. X-ray reflectometry analysis revealed that the film density of the IGZO:H decreased with an increase in R[H<sub>2</sub>] which would be the possible cause for facilitating the O diffusion at low temperature. |
| first_indexed | 2024-03-10T03:32:44Z |
| format | Article |
| id | doaj.art-4d808f57d70349e3bea241a5e67851e6 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-10T03:32:44Z |
| publishDate | 2022-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-4d808f57d70349e3bea241a5e67851e62023-11-23T11:51:42ZengMDPI AGMaterials1996-19442022-01-0115133410.3390/ma15010334Defect Passivation and Carrier Reduction Mechanisms in Hydrogen-Doped In-Ga-Zn-O (IGZO:H) Films upon Low-Temperature Annealing for Flexible Device ApplicationsRostislav Velichko0Yusaku Magari1Mamoru Furuta2Engineering Course, Kochi University of Technology, Kami, Kochi 782-8502, JapanGraduate School of Natural Science and Technology, Shimane University, Matsue, Shimane 690-8504, JapanEngineering Course, Kochi University of Technology, Kami, Kochi 782-8502, JapanLow-temperature activation of oxide semiconductor materials such as In-Ga-Zn-O (IGZO) is a key approach for their utilization in flexible devices. We previously reported that the activation temperature can be reduced to 150 °C by hydrogen-doped IGZO (IGZO:H), demonstrating a strong potential of this approach. In this paper, we investigated the mechanism for reducing the activation temperature of the IGZO:H films. In situ Hall measurements revealed that oxygen diffusion from annealing ambient into the conventional Ar/O<sub>2</sub>-sputtered IGZO film was observed at >240 °C. Moreover, the temperature at which the oxygen diffusion starts into the film significantly decreased to 100 °C for the IGZO:H film deposited at hydrogen gas flow ratio (R[H<sub>2</sub>]) of 8%. Hard X-ray photoelectron spectroscopy indicated that the near Fermi level (E<sub>F</sub>) defects in the IGZO:H film after the 150 °C annealing decreased in comparison to that in the conventional IGZO film after 300 °C annealing. The oxygen diffusion into the film during annealing plays an important role for reducing oxygen vacancies and subgap states especially for near E<sub>F</sub>. X-ray reflectometry analysis revealed that the film density of the IGZO:H decreased with an increase in R[H<sub>2</sub>] which would be the possible cause for facilitating the O diffusion at low temperature.https://www.mdpi.com/1996-1944/15/1/334oxide semiconductorshydrogen in In–Ga–Zn–Odefect passivationoxygen diffusionlow-temperature activationflexible electronics |
| spellingShingle | Rostislav Velichko Yusaku Magari Mamoru Furuta Defect Passivation and Carrier Reduction Mechanisms in Hydrogen-Doped In-Ga-Zn-O (IGZO:H) Films upon Low-Temperature Annealing for Flexible Device Applications Materials oxide semiconductors hydrogen in In–Ga–Zn–O defect passivation oxygen diffusion low-temperature activation flexible electronics |
| title | Defect Passivation and Carrier Reduction Mechanisms in Hydrogen-Doped In-Ga-Zn-O (IGZO:H) Films upon Low-Temperature Annealing for Flexible Device Applications |
| title_full | Defect Passivation and Carrier Reduction Mechanisms in Hydrogen-Doped In-Ga-Zn-O (IGZO:H) Films upon Low-Temperature Annealing for Flexible Device Applications |
| title_fullStr | Defect Passivation and Carrier Reduction Mechanisms in Hydrogen-Doped In-Ga-Zn-O (IGZO:H) Films upon Low-Temperature Annealing for Flexible Device Applications |
| title_full_unstemmed | Defect Passivation and Carrier Reduction Mechanisms in Hydrogen-Doped In-Ga-Zn-O (IGZO:H) Films upon Low-Temperature Annealing for Flexible Device Applications |
| title_short | Defect Passivation and Carrier Reduction Mechanisms in Hydrogen-Doped In-Ga-Zn-O (IGZO:H) Films upon Low-Temperature Annealing for Flexible Device Applications |
| title_sort | defect passivation and carrier reduction mechanisms in hydrogen doped in ga zn o igzo h films upon low temperature annealing for flexible device applications |
| topic | oxide semiconductors hydrogen in In–Ga–Zn–O defect passivation oxygen diffusion low-temperature activation flexible electronics |
| url | https://www.mdpi.com/1996-1944/15/1/334 |
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