Oxidation studies of 4H–SiC( [formula omitted]) and ( [formula omitted])

• Published in: Surface science 2002, Vol.505 (1-3), p.358-366
• Main Authors: Virojanadara, C., Johansson, L.I.
• Format: Article
• Language: English
• Subjects: Adsorbed layers and thin films; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron and ion emission by liquids and solids; impact phenomena; Exact sciences and technology; Oxidation; Photoemission (total yield); Photoemission and photoelectron spectra; Physics; Silicon carbide; Silicon oxides; TECHNOLOGY; TEKNIKVETENSKAP
• ISSN: 0039-6028; 1879-2758; 1879-2758
• DOI: 10.1016/S0039-6028(02)01154-8

The results of a photoemission study of Si- and C-terminated 4H–SiC surfaces after different oxygen exposures are presented and discussed. The surfaces were oxidized gradually from 1 to 1.2×10 6 L at both room temperature and at 800 °C. Recorded Si 2p and C 1s spectra show at both temperatures only two oxidations states, Si 1+ and Si 4+ for the Si-terminated surface and Si 2+ and Si 4+ for the C-terminated surface. For the Si-terminated surface, no carbon containing by-product can be detected at the interface or at the surface after the largest exposure investigated. For the C-terminated surface, oxygen exposures are shown to affect the surface related carbon components quite strongly and the Si 2+ oxidation state is interpreted to originate from a mixture of Si–O–C bonding. The surface/interface related carbon decreases dramatically after the largest exposure investigated but is not eliminated as on the Si-terminated surface. For the latter, a clean and well ordered 3 surface is shown to be possible to re-create by in situ heating even after the largest oxygen exposures made.