【公開日：2023.07.31】【最終更新日：2023.05.28】
課題データ / Project Data
課題番号 / Project Issue Number
22UT1110
利用課題名 / Title
Carbon nanotube field-effect transistor with two-dimensional boron nitride as interface layers
利用した実施機関 / Support Institute
東京大学 / Tokyo Univ.
機関外・機関内の利用 / External or Internal Use
内部利用（ARIM事業参画者以外）/Internal Use (by non ARIM members)
技術領域 / Technology Area
【横断技術領域 / Cross-Technology Area】（主 / Main）加工・デバイスプロセス/Nanofabrication（副 / Sub）-
【重要技術領域 / Important Technology Area】（主 / Main）次世代ナノスケールマテリアル/Next-generation nanoscale materials（副 / Sub）-
キーワード / Keywords
蒸着・成膜/Evaporation and Deposition,ALD,CVD,スパッタリング/Sputtering,リソグラフィ/Lithography,ナノチューブ/ Nanotube
利用者と利用形態 / User and Support Type
利用者名（課題申請者）/ User Name (Project Applicant)
丸山 茂夫
所属名 / Affiliation
東京大学
共同利用者氏名 / Names of Collaborators in Other Institutes Than Hub and Spoke Institutes
Taiki Sugihara,Guangyao Zhu,Ya Feng,Keigo Otsuka,Minhyeok Lee,Rong Xiang,Weijie Jia
ARIM実施機関支援担当者 / Names of Collaborators in The Hub and Spoke Institutes
利用形態 / Support Type
（主 / Main）機器利用/Equipment Utilization（副 / Sub）-
利用した主な設備 / Equipment Used in This Project
KT-103：レーザー直接描画装置
KT-105：両面マスクアライナー
NM-607：スパッタ装置 [CFS-4EP-LL #3]
UT-600：汎用ICPエッチング装置
UT-609：XeF2ドライエッチングシステム
報告書データ / Report
概要（目的・用途・実施内容）/ Abstract (Aim, Use Applications and Contents)
To improve the performance of carbon nanotube (CNT) field-effect transistor (FET), we explore h-BN and CNT heterostructure as channel.
実験 / Experimental
CNTs and h-BN are grown sequentially on a quartz substrate by chemical vapor deposition. The sequential growth of CNTs and h-BN without extra processes guarantees a clean interface. To form a good contact between CNTs and source/drain, we use XeF2 gas to selectively etch the h-BN layers, while the CNTs are only fluorinated. (VPE-4F) Then we deposit Ti/Pd/Au as the source and drain by thermal evaporation, followed by ALD of 15-nm-thick Al2O3 gate dielectric layer. Finally, the gate metal (Ti/Pd/Au) is deposited. All patterns are written by Heidelberg DWL66+.
結果と考察 / Results and Discussion
Figure. 1 (a) and (b) show the structure of our device which typically contains a single CNT as a channel. We get an excellent subthreshold swing of about 69mV/dec, which is close to the theoretical limit at room temperature (60mV/dec). However, the ON current of semiconducting CNT FETs (Fig.1(c)) is much lower than that of metallic CNT FETs (Fig.1(d)). We attribute the small ON current to the fluorination of semiconducting CNTs. Whereas fluorinated metallic CNTs show similar performance to fluorinated graphene [1], fluorinated semiconducting CNTs may form a totally different contact with significant Schottky barrier, leading to large contact resistance. This difference between metallic and semiconducting CNTs needs further investigation.
図・表・数式 / Figures, Tables and Equations
Fig. 1 (a) Schematic illustration of a fabricated CNT FET. (b) SEM image of a fabricated CNT FET. (c, d) Transfer characteristics of FETs with semiconducting CNT (c) and metallic CNT (d).
その他・特記事項（参考文献・謝辞等） / Remarks(References and Acknowledgements)
[1]J. Son et al. Nature Communications. 9, 1-9 (2018).
成果発表・成果利用 / Publication and Patents
論文・プロシーディング（DOIのあるもの） / DOI (Publication and Proceedings)
口頭発表、ポスター発表および、その他の論文 / Oral Presentations etc.
- JIA, W. et al., Carbon nanotube field-effect transistors with two-dimensional boron nitride as interface layers. FNTG (2023).
特許 / Patents
特許出願件数 / Number of Patent Applications：0件
特許登録件数 / Number of Registered Patents：0件