Energy-band alignment of Al2O3 and HfAlO gate dielectrics deposited by atomic layer deposition on 4H-SiC

Article abstract of DOI:10.1063/1.3291620

Energy band alignment and band gap of Al₂O₃ and HfAlO films grown by atomic layer deposition on 4H-SiC were determined using x-ray photoelectron spectroscopy. Al₂O₃ exhibited a symmetric band profile with a conduction band offset (ΔE_C) of 1.88 eV and a valence band offset (ΔE_V) of 1.87 eV. HfAlO yielded a smaller ΔE_C of 1.16 eV and ΔE_V of 1.59 eV. The higher dielectric constant and higher effective breakdown field of HfAlO compared to Al₂O₃, coupled with sufficient electron and hole barrier heights, makes it a potential dielectric for use on 4H-SiC, and provokes interest in further investigation of HfAlO/ 4H-SiC properties.