{"title":"低温退火欧姆接触到超薄algan /GaN异质结构,无二维电子气体","authors":"Kazuya Uryu, Yuchen Deng, Takuma Nanjo, Toshi-kazu Suzuki","doi":"10.1063/5.0260035","DOIUrl":null,"url":null,"abstract":"We investigated low-temperature-annealed Ohmic contacts to ultrathin-AlGaN/GaN heterostructures with no two-dimensional electron gas (2DEG), which have extremely high sheet resistances of ∼1012 Ω/□. The Ohmic contacts are formed by metal deposition and low-temperature annealing at <600 °C, where a contact resistance down to ≃0.74 Ω mm can be realized. In order to evaluate the sheet resistance ρs, the sheet electron concentration ns, and the electron mobility μs of the AlGaN/GaN under the Ohmic-metals, we fabricated and characterized multi-probe Hall devices. As a result, we find ρs significantly decreased down to ∼600 Ω/□, ns in the 1012 cm−2 range, and μs>1000 cm2/V-s under the Ohmic-metals, where the relationship between ns and μs suggests that a 2DEG is formed at the AlGaN/GaN heterointerface. The specific contact resistivity weakly depends on both ns and the measurement temperature, being well explained by direct tunneling between the formed 2DEG and the Ohmic-metal. Furthermore, it is found that the sheet resistance after Ohmic-metal removal returns to the initial value of ∼1012 Ω/□. One possible hypothesis to explain this is that polarization doping takes place under the Ohmic-metals.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"80 1","pages":""},"PeriodicalIF":3.5000,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Low-temperature-annealed Ohmic contacts to ultrathin-AlGaN/GaN heterostructures with no two-dimensional electron gas\",\"authors\":\"Kazuya Uryu, Yuchen Deng, Takuma Nanjo, Toshi-kazu Suzuki\",\"doi\":\"10.1063/5.0260035\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"We investigated low-temperature-annealed Ohmic contacts to ultrathin-AlGaN/GaN heterostructures with no two-dimensional electron gas (2DEG), which have extremely high sheet resistances of ∼1012 Ω/□. The Ohmic contacts are formed by metal deposition and low-temperature annealing at <600 °C, where a contact resistance down to ≃0.74 Ω mm can be realized. In order to evaluate the sheet resistance ρs, the sheet electron concentration ns, and the electron mobility μs of the AlGaN/GaN under the Ohmic-metals, we fabricated and characterized multi-probe Hall devices. As a result, we find ρs significantly decreased down to ∼600 Ω/□, ns in the 1012 cm−2 range, and μs>1000 cm2/V-s under the Ohmic-metals, where the relationship between ns and μs suggests that a 2DEG is formed at the AlGaN/GaN heterointerface. The specific contact resistivity weakly depends on both ns and the measurement temperature, being well explained by direct tunneling between the formed 2DEG and the Ohmic-metal. Furthermore, it is found that the sheet resistance after Ohmic-metal removal returns to the initial value of ∼1012 Ω/□. One possible hypothesis to explain this is that polarization doping takes place under the Ohmic-metals.\",\"PeriodicalId\":8094,\"journal\":{\"name\":\"Applied Physics Letters\",\"volume\":\"80 1\",\"pages\":\"\"},\"PeriodicalIF\":3.5000,\"publicationDate\":\"2025-06-09\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Applied Physics Letters\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://doi.org/10.1063/5.0260035\",\"RegionNum\":2,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"PHYSICS, APPLIED\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Applied Physics Letters","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1063/5.0260035","RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"PHYSICS, APPLIED","Score":null,"Total":0}
Low-temperature-annealed Ohmic contacts to ultrathin-AlGaN/GaN heterostructures with no two-dimensional electron gas
We investigated low-temperature-annealed Ohmic contacts to ultrathin-AlGaN/GaN heterostructures with no two-dimensional electron gas (2DEG), which have extremely high sheet resistances of ∼1012 Ω/□. The Ohmic contacts are formed by metal deposition and low-temperature annealing at <600 °C, where a contact resistance down to ≃0.74 Ω mm can be realized. In order to evaluate the sheet resistance ρs, the sheet electron concentration ns, and the electron mobility μs of the AlGaN/GaN under the Ohmic-metals, we fabricated and characterized multi-probe Hall devices. As a result, we find ρs significantly decreased down to ∼600 Ω/□, ns in the 1012 cm−2 range, and μs>1000 cm2/V-s under the Ohmic-metals, where the relationship between ns and μs suggests that a 2DEG is formed at the AlGaN/GaN heterointerface. The specific contact resistivity weakly depends on both ns and the measurement temperature, being well explained by direct tunneling between the formed 2DEG and the Ohmic-metal. Furthermore, it is found that the sheet resistance after Ohmic-metal removal returns to the initial value of ∼1012 Ω/□. One possible hypothesis to explain this is that polarization doping takes place under the Ohmic-metals.
期刊介绍:
Applied Physics Letters (APL) features concise, up-to-date reports on significant new findings in applied physics. Emphasizing rapid dissemination of key data and new physical insights, APL offers prompt publication of new experimental and theoretical papers reporting applications of physics phenomena to all branches of science, engineering, and modern technology.
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