Fabrication and characterization of metal-semiconductor field-effect transistor utilizing diamond surface-conductive layer

Masahiro Itoh, Hiroshi Kawarada

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Metal-semiconductor field-effect transistors (MESFETs) have been fabricated using the p-type surface-conductive layer of undoped homoepitaxial diamond film on the surface. The layers have been employed as the channel of MESFETs. Since the surface-conductive layer is ultrathin, the depletion region has already closed the surface-conductive channel at the gate voltage of О V, i.e., these MESFETs exhibit the enhancement mode (normally off-mode). The threshold voltages are —1.6 V and —0.7 V in the case of A1 and Pb gate respectively. These MESFETs also exhibit channel pinch-off and complete saturation of drain current, and high transconductance of 2.5 mS/mm at room temperature. This value is the highest of all diamond FETs at present, enhancement/resistor (Е/R) inverters with the enhancement mode transistor and resistor, and direct coupled enhancement/enhance-ment (E/Е) inverters with the two enhancement mode transistors have been also fabricated. This Е/R inverter exhibits high voltage gain. For a E/Е inverter, the voltage gain has also been measured as a function of frequency. The high 3-dB frequency (fн) is above 2 MHz. The voltage gain at frequency =/h (Hz) is equal to l √2~ the voltage gain at frequency = 0 (Hz).

Original languageEnglish
Pages (from-to)4677-4681
Number of pages5
JournalJapanese journal of applied physics
Issue number9R
Publication statusPublished - 1995 Sept


  • Direct coupled E/E inverter
  • E/R inverter
  • Enhancement mode
  • High 3-dB frequency (f)
  • High voltage gain
  • Homoepitaxial CVD diamond
  • Hydrogen termination
  • Surface-conductive layer
  • Transconductance

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)


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