Band structure and alignment of the AlN∕SiC heterostructure

Valence-band structures and band alignments at the AlN∕SiC interface are studied by x-ray photoelectron spectroscopy (XPS) combined with first-principle calculations. Theoretical valence-band structures of SiC and AlN, and band offsets at their interface, were obtained by plane-wave pseudopotential method within the framework of density functional theory. The conduction- and valence-band offsets determined by XPS are 1.3 and 1.7eV, respectively, in excellent agreement with the theoretical values. These relatively large band offsets indicate that AlN is suitable as a gate dielectric or a lattice-matched interfacial layer on SiC.