High energy photoemission investigations of SiO2/SiC samples

• Published in: Applied surface science Vol. 172; no. 3-4; pp. 253 - 259
• Main Authors: VIROJANADARA, C, GLANS, P.-A, JOHANSSON, L. I, EICKHOFF, Th, DRUBE, W
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Science 15-03-2001
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Physics; Surface and interface electron states; Surface states, band structure, electron density of states; TECHNOLOGY; TEKNIKVETENSKAP; Silicon compounds; Electronic structure; Inorganic compounds; Silicon oxides; Surface electron state; Silicon carbides; Solid-solid interfaces; Electronic density of states; Experimental study; Photoelectron spectroscopy
• ISSN: 0169-4332; 1873-5584; 1873-5584
• DOI: 10.1016/S0169-4332(00)00858-8

Chemically etched and directly load-locked SiO2/SiC samples are investigated using a photon energy of 3.0 keV. Si 2p and C 1s spectra recorded at different electron emission angles each show two components originating from SiC, SiO2 and graphite like carbon, respectively. The relative intensity of these are extracted and compared to calculated intensity variations. For the samples investigated, best agreement between experimental and calculated intensity variations is obtained when assuming a graphite like layer on top of the oxide. No graphite like carbon at the SiO2/SiC interface was detected, even on a sample for which the graphite like carbon contribution at the surface corresponds to a layer thickness of only 0.05 angstrom. The energy separation between the oxide and carbide components in the Si 2p spectrum was monitored before and after Ar+ sputtering cycles and before and after in situ heating. The separation increased directly upon sputtering while only in situ heating does not affect it. We suggest that defects induced by the sputtering give rise to the increase, observed in the energy separation.