Low-temperature method for enhancing sputter-deposited Hf O2 films with complete oxidization

A low-temperature method, supercritical C O2 fluid (SCF) technology, is proposed to improve the dielectric properties of ultrathin hafnium oxide (Hf O2) film at 150 °C without significant formation of parasitic oxide at the interface between Hf O2 and Si substrate. In this research, the Hf O2 films were deposited by dc sputter at room temperature and post-treated by SCF which is mixed with 5 vol % propyl alcohol and 5 vol % H2 O. From high-resolution transmission electron microscopy image, the interfacial oxide of SCF-treated Hf O2 film is only 5 Å thick. Additionally, the enhancements in the qualities of sputter-deposited Hf O2 film after SCF process are exhibited by x-ray photoelectron spectroscopy and capacitance-voltage (C-V) measurement.