Electrical characterization of hafnium oxide and hafnium-rich silicate films grown by atomic layer deposition

Abstract

An electrical characterization comparative analysis between Al/HfO 2/n-Si and Al/Hf-Si-O/n-Si samples has been carried out. Hafnium-based dielectric films have been grown by means of atomic layer deposition (ALD). Interface quality have been determined by using capacitance–voltage ( C– V), deep level transient spectroscopy (DLTS) and conductance transient (G-t) techniques. Our results show that silicate films exhibit less flat-band voltage shift and hysteresis effect, and so lower disordered induced gap states (DIGS) density than oxide films, but interfacial state density is greater in Hf–Si–O than in HfO 2. Moreover, a post-deposition annealing in vacuum under N 2 flow for 1 min, at temperatures between 600 and 730 °C diminishes interfacial state density of Hf–Si–O films to values measured in HfO 2 films, without degrade the interface quality in terms of DIGS.