C-Si interface on SiO2/(1 1 1) diamond p-MOSFETs with high mobility and excellent normally-off operation

Xiaohua Zhu, Te Bi, Xiaolu Yuan, Yuhao Chang, Runming Zhang, Yu Fu, Juping Tu, Yabo Huang, Jinlong Liu*, Chengming Li, Hiroshi Kawarada

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


In this paper, a diamond-silicon (C-Si) interface was constructed on a (1 1 1) diamond substrate by annealing the SiO2 gate insulator in a reductive atmosphere. Corresponding metal-oxide-semiconductor field effect transistors (MOSFETs) with a C-Si conductive channel were fabricated. The MOSFETs demonstrate excellent normally-off operation with a high threshold voltage (Vth) of −16 V and a high current density of −167 mA/mm, with a gate length (LG) of 4 μm. The channel hole mobility (μFE) reaches 200 cm2V−1s−1 with a LG of 10 μm, and the interface state density (Dit) is as low as 3.8 × 1011 cm−2 eV−1. The high-resolution transmission electron microscopy (HRTEM) image displays a coherent and strain-free interface between the SiO2 film and (1 1 1) diamond, which ensures a high μFE and low Dit in the MOSFETs. The interface is dominated by C-Si bonds, which are confirmed by atomic-scale electron energy loss (EELS) quantification, spectroscopic characterization, and X-ray photoelectron spectroscopy (XPS). These results demonstrate that diamond, directly combined with SiO2, is ideal for implementation in power devices.

Original languageEnglish
Article number153368
JournalApplied Surface Science
Publication statusPublished - 2022 Aug 15


  • C-Si interface
  • Diamond
  • Normally-off
  • SiO

ASJC Scopus subject areas

  • General Chemistry
  • Condensed Matter Physics
  • General Physics and Astronomy
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films


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