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6CCVD Research

Self-aligned gate electrode for hydrogen-terminated diamond field-effect transistors with a hexagonal boron nitride gate insulator

At a Glance

Section titled ā€œAt a Glanceā€
MetadataDetails
Publication Date2024-08-26
JournalApplied Physics Letters
AuthorsYosuke Sasama, Takuya Iwasaki, Mohammad Monish, Kenji Watanabe, Takashi Taniguchi
InstitutionsNational Institute for Materials Science, University of Tsukuba
Citations3

Abstract

Section titled ā€œAbstractā€

Diamond electronic devices have attracted significant interest owing to their excellent semiconducting properties. We recently demonstrated that eliminating surface-transfer doping enhances carrier mobility and achieves normally off behavior in diamond field-effect transistors (FETs) with a hexagonal boron nitride (h-BN) gate insulator. In our previous study, the gate electrode was overlapped onto the source/drain electrodes to prevent the increase in access resistance caused by excluding surface-transfer doping. However, it is known that gate overlap increases parasitic capacitance and gate leakage current. In this study, we developed a technique for self-aligning the gate electrode with the edge of h-BN using oblique-angle deposition. The diamond FET with a self-aligned gate electrode exhibits optimal FET characteristics, including high mobility of ā‰ˆ 400 cm2Vāˆ’1sāˆ’1, low sheet resistance of 2.4 kĪ©, and output characteristics demonstrating pinch-off behavior. Furthermore, the capacitance-voltage characteristics clearly indicate distinct ON and OFF states, validating the efficacy of this technique. This method enables the fabrication of diamond/h-BN FETs with no gate overlap and without increasing access resistance, making it a promising approach for developing high-speed, low-loss diamond FETs with a wide range of applications.

Tech Support

Section titled ā€œTech Supportā€

Original Source

Section titled ā€œOriginal Sourceā€

References

Section titled ā€œReferencesā€
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  2. 2000 - Origin of surface conductivity in diamond [Crossref]
  3. 2017 - Diamond field-effect transistors for RF power electronics: Novel NO2 hole doping and low-temperature deposited Al2O3 passivation [Crossref]
  4. 2018 - Influence of surface crystal-orientation on transfer doping of V2O5/H-terminated diamond [Crossref]
  5. 2014 - C-H surface diamond field effect transistors for high temperature (400ā€‰Ā°C) and high voltage (500 V) operation [Crossref]
  6. 2017 - Normally-off C-H diamond MOSFETs with partial C-O channel achieving 2-kV breakdown voltage [Crossref]
  7. 2012 - Diamond field-effect transistors with 1.3A/mm drain current density by Al2O3 passivation layer [Crossref]
  8. 2018 - A high frequency hydrogen-terminated diamond MISFET with fT/fmax of 70/80 GHz [Crossref]
  9. 2023 - Irradiation effects of X-rays up to 3 MGy on hydrogen-terminated diamond MOSFETs [Crossref]
  10. 2020 - Charge-carrier mobility in hydrogen-terminated diamond field-effect transistors [Crossref]

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