Epitaxially ideal oxide-semiconductor interfaces: Silicate adlayers on hexagonal (0001) and (000(1)over-bar) SiC surfaces

The preparation of hexagonal {0001} 4H and 6H silicon carbide surfaces by h ydrogen plasma or etching in hydrogen flow produces highly ordered monolaye rs of silicon dioxide. Their structure and epitaxial relationship to the Si C substrate were analyzed by quantitative low-energy electron diffraction a nd Auger electron spectroscopy. The bond angles and distances retrieved agr ee with those of bulk SiO2. Due to the saturation of all dangling bonds the semiconductor surface is passivated and preserves its perfect order also i n air. The practically ideal oxide monolayers may serve as a seed for growi ng epitaxial oxides with low defect density and only few structural distort ions at the interface to the SiC substrate. (C) 1999 American Institute of Physics. [S0003-6951(99)00208-9].