-400 mA mm-1Drain Current Density Normally-Off Polycrystalline Diamond MOSFETs

Xiaohua Zhu, Siwu Shao, Yuhao Chang, Runming Zhang, Sylvia Yuk Yee Chung, Yu Fu, Te Bi, Yabo Huang, Kang An, Jinlong Liu, Chengming Li, Hiroshi Kawarada*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


This letter reports a high drain current density and normally-off operation metal-oxide-semiconductor field-effect transistors (MOSFETs) with a gate insulator of 100 nm-Al2O3. A heavily boron-doped layer as the source/drain region was deposited on a (110) polycrystalline diamond substrate to achieve a low ohmic contact resistance. The MOSFETs demonstrate a maximum current density of -400 mA mm $^{-{1}}$ normalized by gate width and a maximum current density of $- 2000\,\,\mu \text{m}$ mA mm-1 normalized by gate length and gate width, which are the highest values for normally-off diamond FETs. The Grain boundaries (GBs) and the nitrogen impurities ( $\sim {3}\,\,\times \,\,{10}^{{17}}$ cm $^{-{3}}$ ) as ionized donors in the channel region caused the threshold voltage ( ${V}_{\text {th}}$ ) to shift in the negative direction, exhibiting normally-off characteristics. This technique provides a promising method to achieve high-performance diamond devices, and help improve safety and save energy in switching systems.

Original languageEnglish
Pages (from-to)789-792
Number of pages4
JournalIEEE Electron Device Letters
Issue number5
Publication statusPublished - 2022 May 1


  • Diamond
  • high current density
  • hydrogen-termination
  • normally-off

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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