Experimental and First-Principles Studies of the Band Alignment at the HfO2/4H-SiC (0001) Interface
The electronic properties of HfO2 films on 4H-SiC were investigated to determine their suitability as high-κ dielectrics in SiC power MOS devices. The band alignment at the HfO2/4HSiC interface was determined by X-ray photoelectron spectroscopy (XPS) and supported by density functional theory (DFT) calculations. For the experimental study, HfO2 films were deposited on ntype 4H-SiC by atomic layer deposition (ALD). XPS analysis yielded valence and conduction band offsets of 1.69 eV and 0.75 eV, respectively. DFT predictions based on two monoclinic HfO2/4HSiC (0001) structures agree well with this result. The small conduction band offset suggests the potential need for further interface engineering and/or a buffer layer to minimize electron injection into the gate oxide.
Robert P. Devaty, David J. Larkin and Stephen E. Saddow
C. M. Tanner et al., "Experimental and First-Principles Studies of the Band Alignment at the HfO2/4H-SiC (0001) Interface", Materials Science Forum, Vols. 527-529, pp. 1071-1074, 2006