Experimental investigation of the electrical properties of atomic layer deposited hafnium-rich silicate films on n-type silicon

Abstract

This work examines the structural and electrical properties of HfSixOy film based metal-insulator-semiconductor capacitors by means of x-ray diffraction, x-ray photoelectron spectroscopy, capacitance-voltage (C-V), deep level transient spectroscopy, and conductance transient (G-t) techniques. Hafnium-rich silicate films were atomic layer deposited onto HF-etched or SiO2 covered silicon. Although as-deposited samples exhibit high interfacial state and disorder-induced gap state densities, a postdeposition thermal annealing in vacuum under N2 flow for 1min at temperatures between 600 and 730°C clearly improves the interface quality. Marked crystallization and phase separation occurred at 800°C, increasing the structural heterogeneity and defect density in the dielectric oxide layers.