研究課題/領域番号 |
22K04216
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研究種目 |
基盤研究(C)
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配分区分 | 基金 |
応募区分 | 一般 |
審査区分 |
小区分21060:電子デバイスおよび電子機器関連
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研究機関 | 静岡大学 |
研究代表者 |
Moraru Daniel 静岡大学, 電子工学研究所, 准教授 (60549715)
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研究期間 (年度) |
2022-04-01 – 2025-03-31
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研究課題ステータス |
交付 (2022年度)
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配分額 *注記 |
4,160千円 (直接経費: 3,200千円、間接経費: 960千円)
2024年度: 780千円 (直接経費: 600千円、間接経費: 180千円)
2023年度: 1,430千円 (直接経費: 1,100千円、間接経費: 330千円)
2022年度: 1,950千円 (直接経費: 1,500千円、間接経費: 450千円)
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キーワード | Esaki diode / single-electron / donor-acceptor pair / band-to-band tunneling / silicon-on-insulator / nanoscale / dopant quantum dot / silicon nanodevices / wavefunction / phonon |
研究開始時の研究の概要 |
Band-to-band tunneling in Si nanodevices can allow the development of a variety of applications and the exploration of the properties of nanoscale depletion layers. A key aspect is related to the atomistic effects arising from dopant atoms inside and at the edges of the depletion layers. This project will explore the impact of such discrete dopants on band-to-band tunneling, revealing key mechanisms and critical factors for further optimization.
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研究実績の概要 |
The purpose of this research was to elucidate effects of discrete dopants in tunneling currents flowing in Si nanodevices. Exploration of tunneling via dopants in transistors is fundamental for such analysis, for which we studied silicon-on-insulator devices doped with phosphorus (P). As a main target, we also fabricated and studied pn/pin diodes with narrow depletion layers. We reported room-temperature single-electron tunneling in highly-doped SOI transistors, in which multiple-dopant quantum dots can be formed. At low concentrations, single-electron tunneling via single dopants has been analyzed experimentally and theoretically. We also reported steps in band-to-band tunneling current in nanoscale tunnel diodes, ascribed to energy states in the depletion layer.
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現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
By analyzing different silicon-on-insulator (SOI) devices, we could identify signatures of tunneling transport that can be ascribed to the effects of dopants. In transistors doped at low concentrations, we analyzed the possibility of inelastic tunneling through individual donor-atoms each working as a quantum dot (QD). These analyses can provide a base for exploring these effects also in tunnel diodes. In addition, the demonstration of single-electron tunneling at high temperatures (up to room temperature) in nanoscale highly-doped SOI transistors also provides evidence that multiple-dopant-induced QDs can control the tunneling transport significantly in our device configuration. The experimental analysis of tunnel diodes revealed that band-to-band tunneling is affected by energy states in the depletion layer in nanoscale. Analysis is still under way to clarify whether or not these states are directly or indirectly related to the presence of a large number of dopants in the depletion layer. New devices have been fabricated for this purpose and are under analysis. First-principles simulations are being analyzed for gaining a basic understanding of the fundamental physical mechanisms.
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今後の研究の推進方策 |
In the next stage of this research, the basic understanding obtained from the analyses of nanoscale transistors will be applied to the nanoscale SOI tunnel diodes. The first target is to clarify the origin of the current steps or inflections observed in band-to-band tunneling by theoretical and experimental studies on the newly fabricated samples. In parallel, first-principles simulations of Si nanowire pn diodes containing discrete dopants (for instance, a P-donor and a B-acceptor) will be analyzed in detail to develop an insight into the impact of such a donor-acceptor pair on band-to-band tunneling. It is expected that the coupling to the leads and the coupling between the dopants will play key roles in this mechanism. The analysis of the donor-acceptor interactions will also be extended to codoped Si nanoscale transistors, in which single-electron tunneling mechanism was also reported recently by our group (JSAP Fall Meeting 2022). In terms of experiments, the material properties of highly-doped SOI samples will also be analyzed by various methods, providing a more solid base for the understanding of device functionality. New batches of diodes / transistors will be fabricated.
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