Photoemission study of Si-rich 4H-SiC surfaces and initial SiO2 SiC interface formation
2005 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, Vol. 71, no 19Article in journal (Refereed) Published
Photoemission studies of Si-rich polar and nonpolar 4H-SiC surfaces before and after oxygen exposures are reported. For the clean Si-rich (0001) -3×3 surface, three prominent surface-shifted components are revealed in the Si 2p spectrum. This observation agrees well with the structural model suggested for this surface but disagrees with earlier results where only two surface-shifted Si 2p components were identified. Also for the other three Si-rich surfaces investigated three similar surface components are revealed although with different relative strengths. The C 1s spectrum exhibits only one sharp bulk peak for the clean Si-rich surfaces. This is different compared to earlier results from the same surfaces prepared by in situ heating only. The effects induced upon initial oxidation of these Si-rich surfaces are investigated. Recorded Si 2p spectra show only one suboxide, Si+1 and Si+2, for the polar (0001) and (000 1¯) surfaces, respectively, besides the fully developed Si+4 oxide (Si O2). For the nonpolar surfaces two suboxide, Si+1 and Si+2, are observed. Similarities and differences compared to earlier findings are discussed. Valence band spectra collected from clean surfaces, before Si deposition, are presented for the nonpolar surfaces. The presence of a sharp structure at binding energies of about 2.0 and 2.7 eV for the (10 1¯ 0) and the (11 2¯ 0) surfaces, respectively, is observed. This structure shows no dispersion with photon energy and is very sensitive to oxygen exposures and is therefore tentatively suggested to be a surface resonance state. © 2005 The American Physical Society.
Place, publisher, year, edition, pages
2005. Vol. 71, no 19
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-50369DOI: 10.1103/PhysRevB.71.195335OAI: oai:DiVA.org:liu-50369DiVA: diva2:271265