Electronic properties of SiON/HfO2 insulating stacks on 4H-SIC (0001)

V. V. Afanas'ev, S. A. Campbell, K. Y. Cheong, F. Ciobanu, S. Dimitrijev, G. Pensl, A. Stesmans, L. Zhong

Research output: Contribution to journalConference articlepeer-review

9 Scopus citations

Abstract

The application of an insulating stack composed of a few-nm thick thermally grown oxynitride and a thicker (15-20 nm) deposited high-permittivity metal oxide (HfO2, ε ≈20) significantly improves the electrical properties of 4H-SiC(0001) metal-oxide semiconductor (MOS) structures. This is achieved through the beneficial combination of two features: First, the use of a thin native oxynitride allows minimization of the carbon supply from the consumed SiC and, as a consequence, to reduce the density of C-clusters at the SiC/oxide interface. In this way, the density of donor-type interface states near the top of the SiC valence band is reduced to below 1012 cm -2eV-1. Second, the thin oxynitride allows to reduce the density of acceptor-type interface states near the conduction band edge of SiC to values in the low 1012 cm-2eV-1 range, as compared to the high 1012 cm-2eV-1 range observed in thicker oxynitrides or dry oxides on 4H-SiC. The resulting total interface state density in the energy interval of ∼2.7 eV between the Fermi levels in n- and p-type SiC appears to be about 7x1011 cm -2. The attained low interface defect density together with the good insulating properties of the SiON/HfO2 stack suggests that the deposition process does not degrade the underlying oxynitride. This offers the possibility of further optimisation of the stacked insulator for 4H-SiC MOS transistor fabrication.

Original languageEnglish (US)
Pages (from-to)1361-1364
Number of pages4
JournalMaterials Science Forum
Volume457-460
Issue numberII
StatePublished - Jan 1 2004
EventProceedings of the 10th International Conference on Silicon Carbide and Related Materials, ICSCRM 2003 - Lyon, France
Duration: Oct 5 2003Oct 10 2003

Keywords

  • Insulating stack
  • Interface traps
  • Silicon oxynitride
  • Thermal oxidation

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