Systematic structural and chemical characterization of the transition layer at the interface of NO-annealed 4H-SiC/SiO2 metal-oxide-semiconductor field-effect transistors By spherical aberration (C S )-corrected high-resolution transmission electron microscopy (HRTEM) and electron energy-loss spectroscopy (EELS), the atomic and electronic structures at the CrN/Cr interface are studied. A transition layer is formed at the CrN/Cr interface, which is identified as hexagonal Cr 2 N. The atomic structures at the interfaces are revealed. The elemental concentration distribution across the interface was quantified by EELS. The fine structures of Cr-L 2,3 in Cr, CrN, and Cr 2 N exhibit a subtle difference. The Cr-L 2,3 edge in CrN shows a noticeable chemical shift as compared to Cr and Cr 2 N, accompanied by a slight variation at the corresponding N-K edge.