High energy photoemission investigations of SiO2/SiC samples

Chemically etched and directly load-locked SiO2/SiC samples are investigate d using a photon energy of 3.0 keV. Si 2p and C 1s spectra recorded at diff erent electron emission angles each show two components originating from Si C, SiO2 and graphite like carbon, respectively. The relative intensity of t hese are extracted and compared to calculated intensity variations. For the samples investigated, best agreement between experimental acid 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 detect ed, 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 i n situ heating. The separation increased directly upon sputtering while onl y in situ heating does not affect it. We suggest that defects induced by th e sputtering give rise to the increase, observed in the energy separation. (C) 2001 Elsevier Science B.V. All rights reserved.