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Angle‐resolved X‐ray photoelectron spectroscopy of epitaxially grown (100) β‐SiC to 1300 °C
Author(s) -
Wheeler Donald R.,
Pepper Stephen V.
Publication year - 1987
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.740100216
Subject(s) - suboxide , x ray photoelectron spectroscopy , annealing (glass) , materials science , spectral line , epitaxy , analytical chemistry (journal) , photoemission spectroscopy , silicon , oxide , crystallography , layer (electronics) , chemistry , nuclear magnetic resonance , nanotechnology , optoelectronics , physics , astronomy , chromatography , metallurgy , composite material
The (100) surfaces of three β‐Sic crystals grown epitaxially on Si substrates were analyzed by angle‐resolved x‐ray photoelectron spectroscopy (XPS). The specimens were heated by direct current for 2 min in 25 °C increments from 900 to 1300 °C. After each anneal, Si 2p, C 1s and O 1s spectra were obtained for 28° and 64° photoelectron takeoff angles. After annealing below 1150 °C, the Si 2p spectrum has three main lines. One is assigned to SiC, one to SiO 2 and the other to a suboxide. The angular dependence of the intensities of the three features is consistent with 22 A of SiO 2 over 10 Å of suboxide on the SiC substrate. After annealing above 1150 °C, the O 1s and the oxide lines in the Si 2p spectrum gradually decrease, while the C 1s spectrum develops a second line which proved to be due to surface graphite. After heating at 1175 °C the surface was free of oxide and nearly free of graphite. For this surface, C 1s and Si 2p spectra were obtained for electron takeoff angles between 8° and 64°. Comparison of the Si 2p/C 1s ratio with that calculated from a layer model of β‐SiC indicates that the top layer in this state is primarily Si rather than C. After heating above 1200 °C, the second characteristic line in the C 1s spectrum grows. Both the binding energy and characteristic loss features of the new carbon line developed after annealing at high temperatures indicate that it is due to graphite. The angular dependence of the intensities of the two C 1s features indicate that 18 Å of graphite is formed on the surface heated to 1300 °C for 8 min.