  On the basis of ab-initio total-energy electronic-structure calculations, we
find that interface localized electron states at the SiC/SiO$_2$ interface
emerge in the energy region between 0.3 eV below and 1.2 eV above the bulk
conduction-band minimum (CBM) of SiC, being sensitive to the sequence of atomic
bilayers in SiC near the interface. These new interface states unrecognized in
the past are due to the peculiar characteristics of the CBM states which are
distributed along the crystallographic channels. We also find that the electron
doping modifies the energetics among the different stacking structures.
Implication for performance of electron devices fabricated on different SiC
surfaces are discussed.
