Improvement of permittivity of h-BN using super high-k layered dielectric for gate insulator
| Project/Area Number |
17K14656
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Electronic materials/Electric materials
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| Research Institution | Kobe University |
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Principal Investigator |
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| Project Period (FY) |
2017-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2018: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
Fiscal Year 2017: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
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| Keywords | h-BN / F-N tunneling / Fermi level pinning / barrier height / トンネル電流 / バンドアライメント / バリアハイト / ナノ材料 / 電子・電気材料 |
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| Outline of Final Research Achievements |
Hexagonal boron nitride (h-BN) is widely utilized as the substrate to achieve high carrier mobility in a graphene field effect transistor. However, the characteristic of low permittivity in h-BN requires high operating voltages in transistors. The problem can be solved by composite film with high-k and low-k dielectrics. However, the tunneling current goes through the gate insulator in the thin h-BN film as leakage current. However, little systematic study on the tunneling current and band alignment has been conducted for h-BN. We found that the polarity of tunneling current is hole, unlike general oxide material, because the Fermi levels of metals are pinned in the small energy range around 3.5 eV from the top of the conduction band of h-BN with Fermi level pinning.
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| Academic Significance and Societal Importance of the Research Achievements |
h-BNは実用化されているシリコン熱酸化膜（SiO2）に匹敵する絶縁破壊強さや信頼性を有する点から、電子材料としての物性はSiO2に類似点が多いと考えられるが、実際には、SiO2とはバンドアライメントが異なっていて、F-Nトンネル電流に関しては一般的な酸化物絶縁体とは異なり、ホール電流であることを明らかにした。つまり、絶縁破壊において、SiO2は電子電流により破壊され、h-BNはホール電流により破壊される。一方で、通常の酸化物ではフェルミ準位ピンニング起こりにくく、トンネル絶縁膜としても利用されているが、本研究では実験的にh-BNにおいて、ピンニングが確認された。
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Report
(3 results)
Research Products
(7 results)
