Drain Current Density over 1.1 A/mm in 2D Hole Gas Diamond MOSFETs with Regrown p++-Diamond Ohmic Contacts

Shoichiro Imanishi, Ken Kudara, Hitoshi Ishiwata, Kiyotaka Horikawa, Shotaro Amano, Masayuki Iwataki, Aoi Morishita, Atsushi Hiraiwa, Hiroshi Kawarada*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


We report two-dimensional hole gas (2DHG) diamond field-effect transistors (FETs) with microwave plasma chemical vapor deposition (MPCVD)-regrown p+-diamond (B concentration ∼ 1 × 1022 /cm3) ohmic contacts. The heavily doped p+-diamond shows low ohmic contact resistance of 1.1 Ω mm, which is the lowest value reported in diamond to date. In addition, the p+-diamond with a TiC also offers much stronger metal adhesion when compared with previous Au/hydrogen-terminated diamond surfaces and is suitable for industrial use. Benefiting from the low contact resistance of the p+-diamond layer, a maximum drain current density of 1170 mA/mm and an ON-resistance of 8.9 Ω mm were demonstrated in a 2DHG diamond metal-oxide-semiconductor FET with a 1 μm gate length. These results indicate that the regrown p+-diamond ohmic contacts will make it possible to realize further improvements in the maximum drain current density of 2DHG diamond FETs.

Original languageEnglish
Article number9308972
Pages (from-to)204-207
Number of pages4
JournalIEEE Electron Device Letters
Issue number2
Publication statusPublished - 2021 Feb


  • Diamond
  • ON-resistance
  • contact resistance
  • high frequency

ASJC Scopus subject areas

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


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