Two Dimensional Inorganic/Organic Hetero Interface for Normally Off MoS2 FET

2020 Fiscal Year Final Research Report

• Project/Area Number: 17K14662
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Electron device/Electronic equipment
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Kawanago Takamasa 東京工業大学, 科学技術創成研究院, 助教 (30726633)
• Project Period (FY): 2017-04-01 – 2021-03-31
• Keywords: TMDC / FET

Outline of Final Research Achievements

Object of this study is to demonstrate the control of threshold voltage (Vth) by engineering a gate metal electrode in molybdenum disulfide (MoS2) field-effect transistors (FETs). The fabrication process for gate stacks involves the deposition of aluminum oxides (AlOx) on a high-work-function metal and the subsequent formation of a self-assembled monolayer (SAM) by an immersion method. A positive Vth of 0.15V was demonstrated using a platinum (Pt) metal as a gate electrode accompanied by a low density of traps at the interface owing to the close-packed SAM. The Pt gate electrode exhibits a Vth shift of about 1V in the positive direction compared with the aluminum (Al) gate electrode. This Vth shift is consistent with the difference in the work function of Pt and Al gate metal electrodes.

Free Research Field

半導体ナノデバイス

Academic Significance and Societal Importance of the Research Achievements

2次元半導体材料の二硫化モリブデン（MoS2）は移動度が高く、未結合手が無いため化学的、電気的に安定な材料である事から次世代低消費電力エレクトロニクスに向けたFETのチャネル材料として期待されている。本研究によって素子特性で最も重要な閾値電圧制御をMoS2 FETで確立し、正の閾値電圧を実証できた事は次世代低消費電力エレクトロニクスに向けた大きな一歩となり2次元半導体材料の可能性を示す事ができた考えている。