Atomic state and characterization of nitrogen at the SiC/SiO2 interface

Y. Xu, X. Zhu, H. D. Lee, C. Xu, S. M. Shubeita, A. C. Ahyi, Y. Sharma, J. R. Williams, W. Lu, S. Ceesay, B. R. Tuttle, A. Wan, S. T. Pantelides, T. Gustafsson, E. L. Garfunkel, L. C. Feldman

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Abstract

We report on the concentration, chemical bonding, and etching behavior of N at the SiC(0001)/SiO2 interface using photoemission, ion scattering, and computational modeling. For standard NO processing of a SiC MOSFET, a sub-monolayer of nitrogen is found in a thin inter-layer between the substrate and the gate oxide (SiO2). Photoemission shows one main nitrogen related core-level peak with two broad, higher energy satellites. Comparison to theory indicates that the main peak is assigned to nitrogen bound with three silicon neighbors, with second nearest neighbors including carbon, nitrogen, and oxygen atoms. Surprisingly, N remains at the surface after the oxide was completely etched by a buffered HF solution. This is in striking contrast to the behavior of Si(100) undergoing the same etching process. We conclude that N is bound directly to the substrate SiC, or incorporated within the first layers of SiC, as opposed to bonding within the oxide network. These observations provide insights into the chemistry and function of N as an interface passivating additive in SiC MOSFETs.

Original languageEnglish
Article number033502
JournalJournal of Applied Physics
Volume115
Issue number3
DOIs
Publication statusPublished - Feb 10 2014

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ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Xu, Y., Zhu, X., Lee, H. D., Xu, C., Shubeita, S. M., Ahyi, A. C., Sharma, Y., Williams, J. R., Lu, W., Ceesay, S., Tuttle, B. R., Wan, A., Pantelides, S. T., Gustafsson, T., Garfunkel, E. L., & Feldman, L. C. (2014). Atomic state and characterization of nitrogen at the SiC/SiO2 interface. Journal of Applied Physics, 115(3), [033502]. https://doi.org/10.1063/1.4861626