講演情報
[22p-P07-14]Fabrication of field-effect transistors with as-grown clean CNT channels on quartz substrates
〇weijie jia1, Taiki Sugihara1, Guangyao Zhu1, Ya Feng1, Keigo Otsuka1, Minhyeok Lee1, Rong Xiang2, Shigeo Maruyama1, Shohei Chiashi1 (1.The University of Tokyo, 2.Zhejiang University)
キーワード：
semiconductor、FET、CNT
Carbon nanotubes (CNTs) show promise as channel materials for next-gen FETs, offering superior carrier mobility and an ideal one-dimensional structure for GAA devices [1]. A horizontally aligned CNT array, well-suited for FET fabrication, is achieved through Chemical Vapor Deposition (CVD) on quartz [3]. Quartz, favored for RF devices due to lower parasitic capacitance than thermally oxidized silicon, enhances the appeal of fabricating FETs with as-grown CNTs on quartz [4]. This approach eliminates dip-coating and transfers, streamlining procedures, and reducing costs. The absence of surfactants or contamination during separation ensures cleaner CNTs, contributing to improved performance.
In this study, FETs on quartz are fabricated using as-grown CNTs, acknowledging the challenge of achieving 100% semiconducting CNTs through CVD. A deliberate effort is made to synthesize a sparse CNT array, focusing on metallic-free FETs. Calculations of interface trap density assess cleanliness compared to CNTs transferred to thermally oxidized Si. Exploring enhanced protection, the consideration of growing additional hexagonal boron nitride (h-BN) layers through CVD is entertained. For improved contacts, selective XeF2 etching is applied to h-BN in the contact region. Addressing strong CNT-quartz coupling, a weak alkali, TMAH, is employed to etch the quartz substrate and mitigate the coupling effect. TMAH, also a developer in photolithography, ensures minimal additional contamination. Experiments with various etching times aim to observe resulting performance differences.
In this study, FETs on quartz are fabricated using as-grown CNTs, acknowledging the challenge of achieving 100% semiconducting CNTs through CVD. A deliberate effort is made to synthesize a sparse CNT array, focusing on metallic-free FETs. Calculations of interface trap density assess cleanliness compared to CNTs transferred to thermally oxidized Si. Exploring enhanced protection, the consideration of growing additional hexagonal boron nitride (h-BN) layers through CVD is entertained. For improved contacts, selective XeF2 etching is applied to h-BN in the contact region. Addressing strong CNT-quartz coupling, a weak alkali, TMAH, is employed to etch the quartz substrate and mitigate the coupling effect. TMAH, also a developer in photolithography, ensures minimal additional contamination. Experiments with various etching times aim to observe resulting performance differences.