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, Yu Hao 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

Abstract

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
Volume593
DOIs
Publication statusPublished - 2022 Aug 15

Keywords

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

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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