Growth and characterization of UHV sputtering HfO2film by plasma oxidation and low temperature annealing

Abstract

Ultra-thin (∼4.0 nm) HfO2 films were fabricated by plasma oxidation of sputtered metallic Hf films with post low temperature annealing. Advantage of this fabrication process is that the pre-deposition of Hf metal can suppress the formation of interfacial layer between HfO2 film and Si substrate. The as-deposited HfO2 films were subsequently treated by rapid thermal annealing at different temperatures in N2 to investigate the effects of thermal annealing on the physical and electrical properties of HfO2 film. A SiO2-rich interface layer was observed after higher temperature rapid thermal annealing and the phase change of HfO2 film from amorphous into crystalline occurred at about 700°C. As a result of higher temperature annealing, effective dielectric constant and leakage current were significantly influenced by the formation of interface layer and the crystallization of HfO2 film. © Springer Science + Business Media, LLC 2006.