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

Xiaohua Zhu, Siwu Shao, Yu Hao 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

3 Citations (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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