Structural and Morphological Properties of Ultrathin HfO2 Dielectrics on 4H-SiC (0001)
The material properties of HfO2 thin films were studied to evaluate their potential as a high-κ gate dielectric in 4H-SiC power metal-oxide-semiconductor field effect transistors. Stoichiometric HfO2 films were deposited on n-type 4H-SiC (0001) by atomic layer deposition (ALD) at substrate temperatures of 250-450°C. No significant interfacial layer formation was observed by in-situ X-ray photoelectron spectroscopy (XPS) and an abrupt interface was confirmed by high-resolution transmission electron microscopy (HRTEM). A temperature-dependent transition from amorphous layer-by-layer growth to crystalline three-dimensional island growth was identified by in-situ reflection high-energy electron diffraction (RHEED) and ex-situ atomic force microscopy (AFM). X-ray diffraction (XRD) confirmed the presence of monoclinic HfO2 domains in crystallized films.
Robert P. Devaty, David J. Larkin and Stephen E. Saddow
C. M. Tanner et al., "Structural and Morphological Properties of Ultrathin HfO2 Dielectrics on 4H-SiC (0001)", Materials Science Forum, Vols. 527-529, pp. 1075-1078, 2006