Improvement on low-temperature deposited HfO2 film and interfacial layer by high-pressure oxygen treatment

In this study, high-pressure oxygen (O2 and O2 + UV light) technologies were employed to effectively improve the properties of low-temperature-deposited metal oxide dielectric films and interfacial layer. In this work, 13 nm HfO2 thin films were deposited by sputtering method at room temperature. Then, the oxygen treatments with a high-pressure of 1500 psi at 150 °C were performed to replace the conventional high temperature annealing. According to the XPS analyses, integration area of the absorption peaks of O–Hf and O–Hf–Si bonding energies apparently raise and the quantity of oxygen in deposited thin films also increases from XPS measurement. In addition, the leakage current density of standard HfO2 film after O2 and O2 + UV light treatments can be improved from 3.12 × 10−6 A/cm2 to 6.27 × 10−7 and 1.3 × 10−8 A/cm2 at |Vg| = 3 V. The proposed low-temperature and high pressure O2 or O2 + UV light treatment for improving high-k dielectric films is applicable for the future flexible electronics.

► High-pressure oxygen treatments effectively improve the properties of HfO2 film.
► From XPS analyses, the O–Hf and O–Hf–Si bonding energies raise apparently.
► After O2+ UV light treatment, the leakage current density exhibit two orders decrease.
► The conduction mechanism was transformed from trap-assisted tunneling to Schottky emission.
► This low temperature and high pressure oxygen treatment is applicable for the flexible electronics.