Effect of nitrogen passivation on interface composition and physical stress in SiO2/SiC(4H) structures

Xiuyan Li, Sang Soo Lee, Mengjun Li, Alexei Ermakov, Jonnathan Medina-Ramos, Timothy T. Fister, Voshadhi Amarasinghe, Torgny Gustafsson, Eric Garfunkel, Paul Fenter, Leonard C. Feldman

Research output: Contribution to journalArticle

Abstract

The electron density and physical stress at the thermally oxidized SiC/SiO2 interface, and their change with nitrogen incorporation, were observed using x-ray reflectivity, Raman scattering, and in-situ stress measurement. There is no evidence for residual carbon species at the SiO2/SiC. Instead, a ∼1 nm thick low electron density layer is formed at this interface, consistent with interfacial suboxides (SiOx, 0.3 < x < 2), along with high interfacial stress. Nitrogen passivation, a known process to improve the interface state density and electronic properties, eliminates the low density component and simultaneously releases the interface stress. On the basis of these findings, a chemical interaction model is proposed to explain the effect of the nitrogen in terms of both stress reduction and elemental control of the dielectric/SiC interface, resulting in a higher quality gate stack on SiC.

Original languageEnglish
Article number131601
JournalApplied Physics Letters
Volume113
Issue number13
DOIs
Publication statusPublished - Sep 24 2018

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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    Li, X., Lee, S. S., Li, M., Ermakov, A., Medina-Ramos, J., Fister, T. T., Amarasinghe, V., Gustafsson, T., Garfunkel, E., Fenter, P., & Feldman, L. C. (2018). Effect of nitrogen passivation on interface composition and physical stress in SiO2/SiC(4H) structures. Applied Physics Letters, 113(13), [131601]. https://doi.org/10.1063/1.5048220